diff --git a/apps/geolibre-desktop/package.json b/apps/geolibre-desktop/package.json
index f07bae073..e60945699 100644
--- a/apps/geolibre-desktop/package.json
+++ b/apps/geolibre-desktop/package.json
@@ -65,7 +65,7 @@
     "i18next": "^26.3.6",
     "jspdf": "^4.2.1",
     "mapillary-js": "^4.1.2",
-    "maplibre-gl": "^5.24.0",
+    "maplibre-gl": "^6.1.0",
     "maplibre-gl-3d-tiles": "^0.5.6",
     "maplibre-gl-basemap-control": "^0.13.0",
     "maplibre-gl-components": "^0.30.0",
diff --git a/apps/geolibre-desktop/src/components/comments/CommentMapOverlay.tsx b/apps/geolibre-desktop/src/components/comments/CommentMapOverlay.tsx
index f9ab23589..7970fdf92 100644
--- a/apps/geolibre-desktop/src/components/comments/CommentMapOverlay.tsx
+++ b/apps/geolibre-desktop/src/components/comments/CommentMapOverlay.tsx
@@ -1,7 +1,7 @@
 import { useEffect, useRef } from "react";
 import { useAppStore, type ProjectComment } from "@geolibre/core";
 import type { MapController } from "@geolibre/map";
-import maplibreGl from "maplibre-gl";
+import * as maplibreGl from "maplibre-gl";
 
 interface CommentMapOverlayProps {
   mapControllerRef: React.RefObject<MapController | null>;
diff --git a/apps/geolibre-desktop/src/components/comments/useCommentTool.ts b/apps/geolibre-desktop/src/components/comments/useCommentTool.ts
index 1cb35e1e6..41ad3e13d 100644
--- a/apps/geolibre-desktop/src/components/comments/useCommentTool.ts
+++ b/apps/geolibre-desktop/src/components/comments/useCommentTool.ts
@@ -5,7 +5,7 @@ import { useAppStore, type CommentAnchor, type ProjectComment } from "@geolibre/
 import type { MapController } from "@geolibre/map";
 import { v4 as uuidv4 } from "uuid";
 import type { CollaborationApi } from "../../hooks/useCollaboration";
-import type maplibreGl from "maplibre-gl";
+import type * as maplibreGl from "maplibre-gl";
 
 interface UseCommentToolOptions {
   mapControllerRef: React.RefObject<MapController | null>;
diff --git a/apps/geolibre-desktop/src/components/layout/FieldCollectionDialog.tsx b/apps/geolibre-desktop/src/components/layout/FieldCollectionDialog.tsx
index dfeba761c..6e5c082a4 100644
--- a/apps/geolibre-desktop/src/components/layout/FieldCollectionDialog.tsx
+++ b/apps/geolibre-desktop/src/components/layout/FieldCollectionDialog.tsx
@@ -1,6 +1,6 @@
 import { useCallback, useEffect, useId, useMemo, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
-import maplibregl from "maplibre-gl";
+import * as maplibregl from "maplibre-gl";
 import type { MapController } from "@geolibre/map";
 import {
   getAttributeFormField,
diff --git a/apps/geolibre-desktop/src/components/layout/GeoreferencerDialog.tsx b/apps/geolibre-desktop/src/components/layout/GeoreferencerDialog.tsx
index 189f587aa..f266cea25 100644
--- a/apps/geolibre-desktop/src/components/layout/GeoreferencerDialog.tsx
+++ b/apps/geolibre-desktop/src/components/layout/GeoreferencerDialog.tsx
@@ -1,6 +1,6 @@
 import { useCallback, useEffect, useMemo, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
-import type maplibregl from "maplibre-gl";
+import type * as maplibregl from "maplibre-gl";
 import type { MapController } from "@geolibre/map";
 import { DEFAULT_LAYER_STYLE, type GeoLibreLayer, useAppStore } from "@geolibre/core";
 import {
diff --git a/apps/geolibre-desktop/src/components/layout/GpsTrackingDialog.tsx b/apps/geolibre-desktop/src/components/layout/GpsTrackingDialog.tsx
index 2f71f73b2..3b8744241 100644
--- a/apps/geolibre-desktop/src/components/layout/GpsTrackingDialog.tsx
+++ b/apps/geolibre-desktop/src/components/layout/GpsTrackingDialog.tsx
@@ -2,7 +2,7 @@ import { useCallback, useEffect, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
 import type { TFunction } from "i18next";
 import type { Feature, FeatureCollection } from "geojson";
-import maplibregl from "maplibre-gl";
+import * as maplibregl from "maplibre-gl";
 import type { MapController } from "@geolibre/map";
 import { useAppStore } from "@geolibre/core";
 import {
diff --git a/apps/geolibre-desktop/src/components/layout/MapContextMenu.tsx b/apps/geolibre-desktop/src/components/layout/MapContextMenu.tsx
index 0cfc47d94..03b97dc1e 100644
--- a/apps/geolibre-desktop/src/components/layout/MapContextMenu.tsx
+++ b/apps/geolibre-desktop/src/components/layout/MapContextMenu.tsx
@@ -11,7 +11,7 @@ import {
   DropdownMenuSubTrigger,
   DropdownMenuTrigger,
 } from "@geolibre/ui";
-import type maplibregl from "maplibre-gl";
+import type * as maplibregl from "maplibre-gl";
 import {
   BookOpen,
   Braces,
diff --git a/apps/geolibre-desktop/src/components/layout/PixelTimeSeriesControl.tsx b/apps/geolibre-desktop/src/components/layout/PixelTimeSeriesControl.tsx
index d552ef855..7642e19ae 100644
--- a/apps/geolibre-desktop/src/components/layout/PixelTimeSeriesControl.tsx
+++ b/apps/geolibre-desktop/src/components/layout/PixelTimeSeriesControl.tsx
@@ -22,7 +22,7 @@ import {
   useState,
 } from "react";
 import { useTranslation } from "react-i18next";
-import maplibregl from "maplibre-gl";
+import * as maplibregl from "maplibre-gl";
 import type { MapController } from "@geolibre/map";
 import { clamp } from "../../lib/clamp";
 import { type ChartDomain, resolveChartDomain } from "../../lib/chart-domain";
diff --git a/apps/geolibre-desktop/src/components/layout/RemoteCursorsOverlay.tsx b/apps/geolibre-desktop/src/components/layout/RemoteCursorsOverlay.tsx
index e0097be6e..16606828e 100644
--- a/apps/geolibre-desktop/src/components/layout/RemoteCursorsOverlay.tsx
+++ b/apps/geolibre-desktop/src/components/layout/RemoteCursorsOverlay.tsx
@@ -1,5 +1,5 @@
 import { useAppStore, type CollaborationPresence } from "@geolibre/core";
-import maplibregl from "maplibre-gl";
+import * as maplibregl from "maplibre-gl";
 import { useEffect, useRef } from "react";
 import type { RefObject } from "react";
 import type { MapController } from "@geolibre/map";
diff --git a/apps/geolibre-desktop/src/components/panels/LayerPanelPlaceSearch.tsx b/apps/geolibre-desktop/src/components/panels/LayerPanelPlaceSearch.tsx
index 02a9dc29e..3ab7fcbc1 100644
--- a/apps/geolibre-desktop/src/components/panels/LayerPanelPlaceSearch.tsx
+++ b/apps/geolibre-desktop/src/components/panels/LayerPanelPlaceSearch.tsx
@@ -9,7 +9,7 @@ import {
   useState,
 } from "react";
 import { useTranslation } from "react-i18next";
-import maplibregl from "maplibre-gl";
+import * as maplibregl from "maplibre-gl";
 import {
   type GeocodeMatch,
   geocodeForward,
diff --git a/apps/geolibre-desktop/src/components/storymap/StoryMapHandoutDialog.tsx b/apps/geolibre-desktop/src/components/storymap/StoryMapHandoutDialog.tsx
index 869a491e6..2713e8f86 100644
--- a/apps/geolibre-desktop/src/components/storymap/StoryMapHandoutDialog.tsx
+++ b/apps/geolibre-desktop/src/components/storymap/StoryMapHandoutDialog.tsx
@@ -1,5 +1,5 @@
 import { type RefObject, useCallback, useEffect, useMemo, useRef, useState } from "react";
-import maplibregl from "maplibre-gl";
+import * as maplibregl from "maplibre-gl";
 import { useTranslation } from "react-i18next";
 import type { StoryActiveSlideMode, StoryChapter, StoryMap } from "@geolibre/core";
 import type { MapController } from "@geolibre/map";
diff --git a/apps/geolibre-desktop/src/components/storymap/StoryMapPresenter.tsx b/apps/geolibre-desktop/src/components/storymap/StoryMapPresenter.tsx
index 5e9abb80a..4188ccc44 100644
--- a/apps/geolibre-desktop/src/components/storymap/StoryMapPresenter.tsx
+++ b/apps/geolibre-desktop/src/components/storymap/StoryMapPresenter.tsx
@@ -10,7 +10,7 @@ import {
 } from "react";
 import { createPortal } from "react-dom";
 import { useTranslation } from "react-i18next";
-import maplibregl from "maplibre-gl";
+import * as maplibregl from "maplibre-gl";
 import {
   useAppStore,
   type StoryActiveSlideMode,
diff --git a/apps/geolibre-desktop/src/hooks/useCommandBridge.ts b/apps/geolibre-desktop/src/hooks/useCommandBridge.ts
index 16265c402..96b7cd247 100644
Binary files a/apps/geolibre-desktop/src/hooks/useCommandBridge.ts and b/apps/geolibre-desktop/src/hooks/useCommandBridge.ts differ
diff --git a/apps/geolibre-desktop/src/hooks/useNotebookBridge.ts b/apps/geolibre-desktop/src/hooks/useNotebookBridge.ts
index 6c90fe55b..f573ff2ae 100644
--- a/apps/geolibre-desktop/src/hooks/useNotebookBridge.ts
+++ b/apps/geolibre-desktop/src/hooks/useNotebookBridge.ts
@@ -1,5 +1,5 @@
 import { useAppStore } from "@geolibre/core";
-import type maplibregl from "maplibre-gl";
+import type * as maplibregl from "maplibre-gl";
 import { type RefObject, useEffect } from "react";
 import type { MapController } from "@geolibre/map";
 import { createScriptingHandlers } from "../lib/scripting/scriptingApi";
diff --git a/apps/geolibre-desktop/src/lib/assistant/tools.ts b/apps/geolibre-desktop/src/lib/assistant/tools.ts
index cd74b7168..ae67af160 100644
--- a/apps/geolibre-desktop/src/lib/assistant/tools.ts
+++ b/apps/geolibre-desktop/src/lib/assistant/tools.ts
@@ -6,7 +6,7 @@ import {
 } from "@geolibre/core";
 import type { MapController } from "@geolibre/map";
 import type { InvokableTool, JSONValue } from "@strands-agents/sdk";
-import maplibregl from "maplibre-gl";
+import * as maplibregl from "maplibre-gl";
 import { tool } from "@strands-agents/sdk";
 import type { FeatureCollection } from "geojson";
 import { z } from "zod";
diff --git a/apps/geolibre-desktop/src/lib/kml-super-overlay.ts b/apps/geolibre-desktop/src/lib/kml-super-overlay.ts
index 0adcd15ac..ae2bd8992 100644
--- a/apps/geolibre-desktop/src/lib/kml-super-overlay.ts
+++ b/apps/geolibre-desktop/src/lib/kml-super-overlay.ts
@@ -80,10 +80,10 @@ export function setKmlSuperOverlayResolver(resolver: KmlSuperOverlayResolver | n
 async function ensureProtocol(): Promise<void> {
   if (protocolRegistered) return;
   // Keep MapLibre out of tauri-io's static module graph. This also lets the
-  // DOM-only file-loader tests import tauri-io in Node — where maplibre-gl
-  // resolves to its CJS build, so the named exports sit under `default`.
-  const maplibre = await import("maplibre-gl");
-  const addProtocol = maplibre.addProtocol ?? maplibre.default.addProtocol;
+  // DOM-only file-loader tests import tauri-io in Node without pulling the map
+  // in. MapLibre v6 is ESM-only with named exports and no default export, so
+  // this reads `addProtocol` straight off the namespace.
+  const { addProtocol } = await import("maplibre-gl");
   addProtocol(PROTOCOL, handleTileRequest);
   protocolRegistered = true;
 }
diff --git a/apps/geolibre-desktop/src/lib/maplibre-worker.ts b/apps/geolibre-desktop/src/lib/maplibre-worker.ts
new file mode 100644
index 000000000..a8c47a464
--- /dev/null
+++ b/apps/geolibre-desktop/src/lib/maplibre-worker.ts
@@ -0,0 +1,22 @@
+import { setWorkerUrl } from "maplibre-gl";
+// Vite bundles the worker (it imports `./maplibre-gl-shared.mjs`) and hands back
+// the emitted asset URL.
+import maplibreWorkerUrl from "maplibre-gl/dist/maplibre-gl-worker.mjs?worker&url";
+
+/**
+ * Point MapLibre at its bundled worker.
+ *
+ * v6 ships the worker as a **separate file** and locates it at runtime with
+ * `new URL("./maplibre-gl-worker.mjs", import.meta.url)`. That is a computed
+ * string, not a static `new URL(…, import.meta.url)` literal, so no bundler can
+ * see it: the file is never emitted, and at runtime the URL resolves next to the
+ * hashed app chunk (`/assets/maplibre-gl-worker.mjs`), where nothing exists. In
+ * the web build the SPA fallback answers that request with `index.html`, so the
+ * failure is not even a 404 — the worker is handed HTML, and the request hangs
+ * rather than erroring.
+ *
+ * `setWorkerUrl` overrides that lookup with an asset the build actually emits.
+ * Must run before the first `Map` is constructed, so it is imported for effect
+ * from the app entry.
+ */
+setWorkerUrl(maplibreWorkerUrl);
diff --git a/apps/geolibre-desktop/src/lib/print-layout-export.ts b/apps/geolibre-desktop/src/lib/print-layout-export.ts
index d0ff028f2..7edb4fa2e 100644
--- a/apps/geolibre-desktop/src/lib/print-layout-export.ts
+++ b/apps/geolibre-desktop/src/lib/print-layout-export.ts
@@ -6,7 +6,7 @@
  * export helpers rasterize {@link drawLayout} at print resolution.
  */
 import { zipSync } from "fflate";
-import jsPDF from "jspdf";
+import { jsPDF } from "jspdf";
 import { isFullViewportMapCanvas } from "./print-capture";
 import { drawLayout, pageMm, pagePx, resolvePageSize, type LayoutOptions } from "./print-layout";
 import type { PrintExtent } from "./print-extent";
diff --git a/apps/geolibre-desktop/src/lib/rtl-text.ts b/apps/geolibre-desktop/src/lib/rtl-text.ts
index 011629a34..d71efdf3e 100644
--- a/apps/geolibre-desktop/src/lib/rtl-text.ts
+++ b/apps/geolibre-desktop/src/lib/rtl-text.ts
@@ -1,4 +1,4 @@
-import maplibregl from "maplibre-gl";
+import * as maplibregl from "maplibre-gl";
 // Vite resolves this to a hashed, same-origin asset URL at build time, so the
 // RTL plugin ships with the app (web, desktop, and the Jupyter embed) instead of
 // being fetched from a CDN — keeps every build's CSP simple and works offline.
diff --git a/apps/geolibre-desktop/src/lib/storymap-pdf.ts b/apps/geolibre-desktop/src/lib/storymap-pdf.ts
index ff25c7318..36c980662 100644
--- a/apps/geolibre-desktop/src/lib/storymap-pdf.ts
+++ b/apps/geolibre-desktop/src/lib/storymap-pdf.ts
@@ -10,7 +10,7 @@
  * stays free of MapLibre and the DOM and can be unit tested with data-URL
  * images.
  */
-import jsPDF from "jspdf";
+import { jsPDF } from "jspdf";
 import { pageMm, resolvePageSize, type Orientation, type PaperSizeId } from "./print-layout";
 
 /** An image to embed: a canvas (app) or a PNG/JPEG data URL (tests), plus its
diff --git a/apps/geolibre-desktop/src/main.tsx b/apps/geolibre-desktop/src/main.tsx
index bf9407156..ba4bc7966 100644
--- a/apps/geolibre-desktop/src/main.tsx
+++ b/apps/geolibre-desktop/src/main.tsx
@@ -1,4 +1,6 @@
 import "./lib/symbol-dispose-polyfill";
+// Must precede any Map construction (see the module docs).
+import "./lib/maplibre-worker";
 import React from "react";
 import ReactDOM from "react-dom/client";
 import "@geoman-io/maplibre-geoman-free/dist/maplibre-geoman.css";
diff --git a/apps/geolibre-desktop/vite-plugins/maplibre-default-import-shim.ts b/apps/geolibre-desktop/vite-plugins/maplibre-default-import-shim.ts
new file mode 100644
index 000000000..7e001f9d3
--- /dev/null
+++ b/apps/geolibre-desktop/vite-plugins/maplibre-default-import-shim.ts
@@ -0,0 +1,67 @@
+import type { Plugin } from "vite";
+
+/**
+ * Rewrite `import X from "maplibre-gl"` to `import * as X from "maplibre-gl"`
+ * inside the published bundles of packages that still target MapLibre v5.
+ *
+ * MapLibre v6 is ESM-only with **no default export**, so a dist file compiled
+ * against v5's default export is a hard bundling error:
+ *
+ *     [MISSING_EXPORT] "default" is not exported by ".../maplibre-gl.mjs"
+ *
+ * A namespace object is a drop-in for what these bundles actually do with the
+ * binding (`X.Map`, `new X.Popup()`, …), so the rewrite is safe.
+ *
+ * This is a **temporary** shim for third-party packages we do not control. Every
+ * opengeos-owned package has already been migrated and released, so the list
+ * below should only ever shrink. See opengeos/GeoLibre#1489 (blocker 1).
+ *
+ * The plugin fails the build if a listed package stops matching — that means it
+ * either shipped a fix (delete the entry) or changed its bundle shape (revisit),
+ * and silently shimming nothing would hide both.
+ */
+const SHIMMED_PACKAGES = ["@esri/maplibre-arcgis", "@geoman-io/maplibre-geoman-free"] as const;
+
+// Matches a default import of maplibre-gl in minified or unminified ESM:
+//   import Zt from"maplibre-gl"     import e from "maplibre-gl"
+const DEFAULT_IMPORT = /\bimport\s+([A-Za-z_$][\w$]*)\s+from\s*(["'])maplibre-gl\2/g;
+
+export function maplibreDefaultImportShim(): Plugin {
+  const rewritten = new Set<string>();
+
+  return {
+    name: "geolibre:maplibre-default-import-shim",
+    enforce: "pre",
+    apply: () => true,
+
+    transform(code, id) {
+      const pkg = SHIMMED_PACKAGES.find((name) => id.includes(`/node_modules/${name}/`));
+      if (!pkg || !code.includes("maplibre-gl")) return null;
+
+      DEFAULT_IMPORT.lastIndex = 0;
+      if (!DEFAULT_IMPORT.test(code)) return null;
+
+      rewritten.add(pkg);
+      DEFAULT_IMPORT.lastIndex = 0;
+      return {
+        code: code.replace(
+          DEFAULT_IMPORT,
+          (_match, binding: string, quote: string) =>
+            `import * as ${binding} from ${quote}maplibre-gl${quote}`,
+        ),
+        map: null,
+      };
+    },
+
+    buildEnd(error) {
+      if (error) return;
+      const stale = SHIMMED_PACKAGES.filter((name) => !rewritten.has(name));
+      if (stale.length === 0) return;
+      this.error(
+        `maplibre default-import shim matched nothing in: ${stale.join(", ")}. ` +
+          `If the package now ships a v6-compatible build, remove it from ` +
+          `SHIMMED_PACKAGES in vite-plugins/maplibre-default-import-shim.ts.`,
+      );
+    },
+  };
+}
diff --git a/apps/geolibre-desktop/vite.config.ts b/apps/geolibre-desktop/vite.config.ts
index 47a0956fd..4b9e1f61d 100644
--- a/apps/geolibre-desktop/vite.config.ts
+++ b/apps/geolibre-desktop/vite.config.ts
@@ -11,6 +11,7 @@ import { bundledPlugins } from "./vite-plugins/bundled-plugins";
 import { copyCesiumAssets } from "./vite-plugins/copy-cesium-assets";
 import { copyRtlText } from "./vite-plugins/copy-rtl-text";
 import { copyVectorOps } from "./vite-plugins/copy-vector-ops";
+import { maplibreDefaultImportShim } from "./vite-plugins/maplibre-default-import-shim";
 import { proxyBinaryRequestGuarded } from "./vite-proxy-guard";
 
 const GEOAGENT_BROWSER_BUNDLE = "maplibre-gl-geoagent/dist/browser-";
@@ -846,6 +847,7 @@ function pwaPlugin(): Plugin[] {
 export default defineConfig({
   base: APP_BASE,
   plugins: [
+    maplibreDefaultImportShim(),
     ...(PGLITE_CDN ? [pgliteCdnLoaderPlugin()] : []),
     ...(CEREUS_CDN ? [cereusCdnLoaderPlugin()] : []),
     duckdbWasmBundlesPlugin(),
@@ -959,6 +961,13 @@ export default defineConfig({
       // asset reference, so serve it as-is. Only reached through the lazy
       // dynamic import in local-netcdf.ts when a user opens a local file.
       "h5wasm",
+      // These two still default-import maplibre-gl, which v6 does not provide.
+      // `maplibreDefaultImportShim` rewrites that, but the dependency optimizer
+      // runs outside the plugin pipeline and would fail before the shim is ever
+      // consulted, so serve them unbundled and let the shim transform them.
+      // Remove alongside their entries in the shim. See opengeos/GeoLibre#1489.
+      "@esri/maplibre-arcgis",
+      "@geoman-io/maplibre-geoman-free",
     ],
   },
   build: {
diff --git a/package-lock.json b/package-lock.json
index d9f97f0ba..633030b22 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -78,7 +78,7 @@
         "i18next": "^26.3.6",
         "jspdf": "^4.2.1",
         "mapillary-js": "^4.1.2",
-        "maplibre-gl": "^5.24.0",
+        "maplibre-gl": "^6.1.0",
         "maplibre-gl-3d-tiles": "^0.5.6",
         "maplibre-gl-basemap-control": "^0.13.0",
         "maplibre-gl-components": "^0.30.0",
@@ -5447,9 +5447,9 @@
       "license": "BSD-2-Clause"
     },
     "node_modules/@mapbox/unitbezier": {
-      "version": "0.0.1",
-      "resolved": "https://registry.npmjs.org/@mapbox/unitbezier/-/unitbezier-0.0.1.tgz",
-      "integrity": "sha512-nMkuDXFv60aBr9soUG5q+GvZYL+2KZHVvsqFCzqnkGEf46U2fvmytHaEVc1/YZbiLn8X+eR3QzX1+dwDO1lxlw==",
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/@mapbox/unitbezier/-/unitbezier-1.0.0.tgz",
+      "integrity": "sha512-fqd515fjBmANKGGsQ286E2Wvj/XvDFpGzwJxq4CI6jMQue6Oy04uCKp+JWKF00xRTmk6cEu1jPJ9p3xqH8YWqQ==",
       "license": "BSD-2-Clause"
     },
     "node_modules/@mapbox/vector-tile": {
@@ -5461,15 +5461,6 @@
         "@mapbox/point-geometry": "~0.1.0"
       }
     },
-    "node_modules/@mapbox/whoots-js": {
-      "version": "3.1.0",
-      "resolved": "https://registry.npmjs.org/@mapbox/whoots-js/-/whoots-js-3.1.0.tgz",
-      "integrity": "sha512-Es6WcD0nO5l+2BOQS4uLfNPYQaNDfbot3X1XUoloz+x0mPDS3eeORZJl06HXjwBG1fOGwCRnzK88LMdxKRrd6Q==",
-      "license": "ISC",
-      "engines": {
-        "node": ">=6.0.0"
-      }
-    },
     "node_modules/@maplibre/geojson-vt": {
       "version": "6.1.1",
       "resolved": "https://registry.npmjs.org/@maplibre/geojson-vt/-/geojson-vt-6.1.1.tgz",
@@ -5493,12 +5484,12 @@
       }
     },
     "node_modules/@maplibre/maplibre-gl-style-spec": {
-      "version": "24.10.0",
-      "resolved": "https://registry.npmjs.org/@maplibre/maplibre-gl-style-spec/-/maplibre-gl-style-spec-24.10.0.tgz",
-      "integrity": "sha512-lichxSiagMEBBrqHF0trtMQH9RKh+9jUlIJl0qW0QHvt2H/tbvUWdE+ZzI2Jd0/pT7j/iavLonlPu7EQ/ixTOw==",
+      "version": "26.2.1",
+      "resolved": "https://registry.npmjs.org/@maplibre/maplibre-gl-style-spec/-/maplibre-gl-style-spec-26.2.1.tgz",
+      "integrity": "sha512-QFKCXkOeSzOr8jF75jm6kySOg+dUvOehPhRi68gcOYPHb7U5JloUq0dJW0Y5/fZV8ygfT0Vp2RWodvq+fyxFWA==",
       "license": "ISC",
       "dependencies": {
-        "@mapbox/jsonlint-lines-primitives": "~2.0.2",
+        "@mapbox/jsonlint-lines-primitives": "^2.0.3",
         "@mapbox/unitbezier": "^1.0.0",
         "json-stringify-pretty-compact": "^4.0.0",
         "minimist": "^1.2.8",
@@ -5511,12 +5502,6 @@
         "gl-style-validate": "dist/gl-style-validate.mjs"
       }
     },
-    "node_modules/@maplibre/maplibre-gl-style-spec/node_modules/@mapbox/unitbezier": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/@mapbox/unitbezier/-/unitbezier-1.0.0.tgz",
-      "integrity": "sha512-fqd515fjBmANKGGsQ286E2Wvj/XvDFpGzwJxq4CI6jMQue6Oy04uCKp+JWKF00xRTmk6cEu1jPJ9p3xqH8YWqQ==",
-      "license": "BSD-2-Clause"
-    },
     "node_modules/@maplibre/maplibre-gl-style-spec/node_modules/tinyqueue": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/tinyqueue/-/tinyqueue-3.0.0.tgz",
@@ -16776,27 +16761,25 @@
       "license": "MIT"
     },
     "node_modules/maplibre-gl": {
-      "version": "5.24.0",
-      "resolved": "https://registry.npmjs.org/maplibre-gl/-/maplibre-gl-5.24.0.tgz",
-      "integrity": "sha512-ALyFxgtd5R+65UqZ/++lOqwWcC0SNho9c27fYSyLmG7AfnAul2o46F05aDJGPbFU57wos9dgcIySHs0Xe6ia3A==",
+      "version": "6.1.0",
+      "resolved": "https://registry.npmjs.org/maplibre-gl/-/maplibre-gl-6.1.0.tgz",
+      "integrity": "sha512-vLRukjvbUai4SXW2/jKo8rPsw6YMXuA/b4fKFVSulZKFVRHkOvk4ZmNlDSVZpTYPV0/7/iTqq8ltYdyr764b7w==",
       "license": "BSD-3-Clause",
       "dependencies": {
-        "@mapbox/jsonlint-lines-primitives": "^2.0.2",
         "@mapbox/point-geometry": "^1.1.0",
-        "@mapbox/tiny-sdf": "^2.1.0",
-        "@mapbox/unitbezier": "^0.0.1",
-        "@mapbox/vector-tile": "^2.0.4",
-        "@mapbox/whoots-js": "^3.1.0",
-        "@maplibre/geojson-vt": "^6.1.0",
-        "@maplibre/maplibre-gl-style-spec": "^24.8.1",
-        "@maplibre/mlt": "^1.1.8",
-        "@maplibre/vt-pbf": "^4.3.0",
+        "@mapbox/tiny-sdf": "^2.2.0",
+        "@mapbox/unitbezier": "^1.0.0",
+        "@mapbox/vector-tile": "^3.0.0",
+        "@maplibre/geojson-vt": "^6.1.1",
+        "@maplibre/maplibre-gl-style-spec": "^26.2.1",
+        "@maplibre/mlt": "^1.1.12",
+        "@maplibre/vt-pbf": "^4.3.2",
         "@types/geojson": "^7946.0.16",
-        "earcut": "^3.0.2",
+        "earcut": "^3.2.3",
         "gl-matrix": "^3.4.4",
-        "kdbush": "^4.0.2",
+        "kdbush": "^4.1.0",
         "murmurhash-js": "^1.0.0",
-        "pbf": "^4.0.1",
+        "pbf": "^5.1.2",
         "potpack": "^2.1.0",
         "quickselect": "^3.0.0",
         "tinyqueue": "^3.0.0"
@@ -17482,14 +17465,14 @@
       "license": "ISC"
     },
     "node_modules/maplibre-gl/node_modules/@mapbox/vector-tile": {
-      "version": "2.0.5",
-      "resolved": "https://registry.npmjs.org/@mapbox/vector-tile/-/vector-tile-2.0.5.tgz",
-      "integrity": "sha512-pXj8m7KTsqZt+1jsE0xIpGvqTSbblfkuEJL/NJmNePMtEwxO8V3XMDo9WMSfDeqHvCtBI9Lmt4mGcGR10zecmw==",
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/@mapbox/vector-tile/-/vector-tile-3.0.0.tgz",
+      "integrity": "sha512-Qf10S1uIHMk20ri/IVBnpS+esUEkVaR5Hftmz88jTInrpmWgPGJfPe3LVjjlE77trLx8tH6qjTG7uWH9hIq/0Q==",
       "license": "BSD-3-Clause",
       "dependencies": {
         "@mapbox/point-geometry": "~1.1.0",
         "@types/geojson": "^7946.0.16",
-        "pbf": "^4.0.2"
+        "pbf": "^5.0.0"
       }
     },
     "node_modules/maplibre-gl/node_modules/earcut": {
@@ -17498,6 +17481,18 @@
       "integrity": "sha512-vnS4AVwp1KHAF13i1vp1/2D5evWy3k5u/iW/B81QVsUZtV8cv2tU0b2VNFlqvh4kYwrFMDdjPCfAmfyJW9y14Q==",
       "license": "ISC"
     },
+    "node_modules/maplibre-gl/node_modules/pbf": {
+      "version": "5.1.2",
+      "resolved": "https://registry.npmjs.org/pbf/-/pbf-5.1.2.tgz",
+      "integrity": "sha512-mnvGdvOrIvJOBGUEdGkrVXjN8E/VkIJCkf2eS1DH2yv82ORUlLttmDt0rWY38yYZmVwciZwBUvHM20qxBZf40w==",
+      "license": "BSD-3-Clause",
+      "dependencies": {
+        "resolve-protobuf-schema": "^2.1.0"
+      },
+      "bin": {
+        "pbf": "bin/pbf"
+      }
+    },
     "node_modules/maplibre-gl/node_modules/tinyqueue": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/tinyqueue/-/tinyqueue-3.0.0.tgz",
@@ -22233,37 +22228,6 @@
         "typescript": "^7.0.2"
       }
     },
-    "packages/core/node_modules/@mapbox/unitbezier": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/@mapbox/unitbezier/-/unitbezier-1.0.0.tgz",
-      "integrity": "sha512-fqd515fjBmANKGGsQ286E2Wvj/XvDFpGzwJxq4CI6jMQue6Oy04uCKp+JWKF00xRTmk6cEu1jPJ9p3xqH8YWqQ==",
-      "license": "BSD-2-Clause"
-    },
-    "packages/core/node_modules/@maplibre/maplibre-gl-style-spec": {
-      "version": "26.2.1",
-      "resolved": "https://registry.npmjs.org/@maplibre/maplibre-gl-style-spec/-/maplibre-gl-style-spec-26.2.1.tgz",
-      "integrity": "sha512-QFKCXkOeSzOr8jF75jm6kySOg+dUvOehPhRi68gcOYPHb7U5JloUq0dJW0Y5/fZV8ygfT0Vp2RWodvq+fyxFWA==",
-      "license": "ISC",
-      "dependencies": {
-        "@mapbox/jsonlint-lines-primitives": "^2.0.3",
-        "@mapbox/unitbezier": "^1.0.0",
-        "json-stringify-pretty-compact": "^4.0.0",
-        "minimist": "^1.2.8",
-        "quickselect": "^3.0.0",
-        "tinyqueue": "^3.0.0"
-      },
-      "bin": {
-        "gl-style-format": "dist/gl-style-format.mjs",
-        "gl-style-migrate": "dist/gl-style-migrate.mjs",
-        "gl-style-validate": "dist/gl-style-validate.mjs"
-      }
-    },
-    "packages/core/node_modules/tinyqueue": {
-      "version": "3.0.0",
-      "resolved": "https://registry.npmjs.org/tinyqueue/-/tinyqueue-3.0.0.tgz",
-      "integrity": "sha512-gRa9gwYU3ECmQYv3lslts5hxuIa90veaEcxDYuu3QGOIAEM2mOZkVHp48ANJuu1CURtRdHKUBY5Lm1tHV+sD4g==",
-      "license": "ISC"
-    },
     "packages/core/node_modules/typescript": {
       "version": "7.0.2",
       "resolved": "https://registry.npmjs.org/typescript/-/typescript-7.0.2.tgz",
@@ -22359,7 +22323,7 @@
         "@turf/mask": "^7.3.5",
         "cesium": "^1.143.0",
         "fast-xml-parser": "^5.10.1",
-        "maplibre-gl": "^5.24.0",
+        "maplibre-gl": "^6.1.0",
         "maplibre-gl-layer-control": "^0.17.4",
         "pmtiles": "^4.4.1",
         "react": "^19.2.8",
@@ -22445,7 +22409,7 @@
         "h5wasm": "^0.10.3",
         "jspdf": "^4.2.1",
         "mapillary-js": "^4.1.2",
-        "maplibre-gl": "^5.24.0",
+        "maplibre-gl": "^6.1.0",
         "maplibre-gl-3d-tiles": "^0.5.6",
         "maplibre-gl-basemap-control": "^0.13.0",
         "maplibre-gl-components": "^0.30.0",
diff --git a/package.json b/package.json
index ea441be9c..079034fb9 100644
--- a/package.json
+++ b/package.json
@@ -16,8 +16,8 @@
     "typecheck": "npm run build",
     "lint": "eslint apps packages workers tests",
     "test": "npm run test:frontend",
-    "test:frontend": "node --import tsx --test tests/*.test.ts",
-    "test:frontend:coverage": "node --import tsx --test --experimental-test-coverage --test-coverage-lines=78 --test-coverage-branches=78 --test-coverage-functions=63 --test-coverage-exclude=\"tests/**\" --test-coverage-exclude=\"e2e/**\" --test-coverage-exclude=\"**/*.config.*\" tests/*.test.ts",
+    "test:frontend": "node --import ./tests/hooks/register-maplibre-shim.mjs --import tsx --test tests/*.test.ts",
+    "test:frontend:coverage": "node --import ./tests/hooks/register-maplibre-shim.mjs --import tsx --test --experimental-test-coverage --test-coverage-lines=78 --test-coverage-branches=78 --test-coverage-functions=63 --test-coverage-exclude=\"tests/**\" --test-coverage-exclude=\"e2e/**\" --test-coverage-exclude=\"**/*.config.*\" tests/*.test.ts",
     "test:backend": "python -m pytest backend/geolibre_server/tests",
     "test:backend:coverage": "python -m pytest backend/geolibre_server/tests --cov=geolibre_server --cov-report=term-missing --cov-fail-under=55",
     "test:worker": "npm run typecheck -w geolibre-viewer-worker && npm run typecheck -w geolibre-collab-worker && npm run typecheck -w geolibre-collab-node && npm test -w geolibre-collab-node && npm run typecheck -w geolibre-tiles-worker && npm run typecheck -w geolibre-ai-proxy-worker",
@@ -46,6 +46,7 @@
     "brace-expansion": "^5.0.8",
     "fast-uri": "^3.1.5",
     "filelist": "^2.0.2",
+    "maplibre-gl": "^6.1.0",
     "sweepline-intersections": "^1.5.0",
     "uuid": "^14.0.0"
   },
diff --git a/packages/map/package.json b/packages/map/package.json
index 6b98f026f..e7f686abb 100644
--- a/packages/map/package.json
+++ b/packages/map/package.json
@@ -22,7 +22,7 @@
     "@turf/mask": "^7.3.5",
     "cesium": "^1.143.0",
     "fast-xml-parser": "^5.10.1",
-    "maplibre-gl": "^5.24.0",
+    "maplibre-gl": "^6.1.0",
     "maplibre-gl-layer-control": "^0.17.4",
     "pmtiles": "^4.4.1",
     "react": "^19.2.8",
diff --git a/packages/map/src/MapCanvas.tsx b/packages/map/src/MapCanvas.tsx
index fb3a230c1..1caf1241f 100644
--- a/packages/map/src/MapCanvas.tsx
+++ b/packages/map/src/MapCanvas.tsx
@@ -6,7 +6,7 @@ import {
   useAppStore,
   type GeoLibreLayer,
 } from "@geolibre/core";
-import maplibregl from "maplibre-gl";
+import * as maplibregl from "maplibre-gl";
 import { memo, useEffect, useMemo, useRef } from "react";
 import {
   circleLayerId,
diff --git a/packages/map/src/collapsed-attribution-control.ts b/packages/map/src/collapsed-attribution-control.ts
index d8f3675ee..16391e266 100644
--- a/packages/map/src/collapsed-attribution-control.ts
+++ b/packages/map/src/collapsed-attribution-control.ts
@@ -1,4 +1,4 @@
-import maplibregl from "maplibre-gl";
+import * as maplibregl from "maplibre-gl";
 
 /** Set by MapLibre once the control is in compact (collapsible) mode. */
 const COMPACT_CLASS = "maplibregl-compact";
diff --git a/packages/map/src/dynamic-style-property.ts b/packages/map/src/dynamic-style-property.ts
new file mode 100644
index 000000000..854e31507
--- /dev/null
+++ b/packages/map/src/dynamic-style-property.ts
@@ -0,0 +1,58 @@
+/**
+ * Escape hatches for style properties whose names are only known at runtime.
+ *
+ * MapLibre v6 made `set/getPaintProperty` and `set/getLayoutProperty` generic
+ * over `keyof AllPaintProperties` / `keyof AllLayoutProperties`, so they accept
+ * only literal property names the compiler can see. GeoLibre computes property
+ * names in several places that the type system cannot follow:
+ *
+ * - iterating `Object.entries(spec.paint)` when applying a whole style block,
+ * - building transition names as `` `${prop}-transition` ``,
+ * - taking a `property: string` parameter through a generic helper.
+ *
+ * Each needs a cast. They live here — one documented module — rather than being
+ * sprinkled at every call site, so the blast radius is visible if MapLibre
+ * tightens or relaxes these signatures again. Prefer the typed MapLibre methods
+ * whenever the property name *is* a literal; reach for these only when it is not.
+ */
+
+/**
+ * The slice of a MapLibre `Map` these helpers reach through.
+ *
+ * The getters are optional: they are read to skip no-op writes, and some
+ * external-control and test map objects implement only the setters. A missing
+ * getter must degrade to "unknown current value" (write anyway), never throw.
+ * The setters are required — silently dropping a write would be a real bug.
+ */
+interface DynamicStyleTarget {
+  setPaintProperty: (layerId: string, property: string, value: unknown) => void;
+  getPaintProperty?: (layerId: string, property: string) => unknown;
+  setLayoutProperty: (layerId: string, property: string, value: unknown) => void;
+  getLayoutProperty?: (layerId: string, property: string) => unknown;
+}
+
+export function setDynamicPaintProperty(
+  map: object,
+  layerId: string,
+  property: string,
+  value: unknown,
+): void {
+  (map as DynamicStyleTarget).setPaintProperty(layerId, property, value);
+}
+
+export function getDynamicPaintProperty(map: object, layerId: string, property: string): unknown {
+  return (map as DynamicStyleTarget).getPaintProperty?.(layerId, property);
+}
+
+export function setDynamicLayoutProperty(
+  map: object,
+  layerId: string,
+  property: string,
+  value: unknown,
+): void {
+  (map as DynamicStyleTarget).setLayoutProperty(layerId, property, value);
+}
+
+export function getDynamicLayoutProperty(map: object, layerId: string, property: string): unknown {
+  return (map as DynamicStyleTarget).getLayoutProperty?.(layerId, property);
+}
diff --git a/packages/map/src/generated-images.ts b/packages/map/src/generated-images.ts
index a056036bb..caaa58c60 100644
--- a/packages/map/src/generated-images.ts
+++ b/packages/map/src/generated-images.ts
@@ -1,4 +1,4 @@
-import type maplibregl from "maplibre-gl";
+import type * as maplibregl from "maplibre-gl";
 
 /**
  * Lazily-generated MapLibre sprite images (fill-pattern tiles and marker icons).
diff --git a/packages/map/src/layer-sync.ts b/packages/map/src/layer-sync.ts
index 1ba5fac24..3293d715b 100644
--- a/packages/map/src/layer-sync.ts
+++ b/packages/map/src/layer-sync.ts
@@ -15,7 +15,7 @@ import {
 } from "@geolibre/core";
 import { addProtocol, config } from "maplibre-gl";
 import type { GeoJSON } from "geojson";
-import type maplibregl from "maplibre-gl";
+import type * as maplibregl from "maplibre-gl";
 import type { PropertyValueSpecification } from "maplibre-gl";
 import { FileSource, PMTiles, Protocol } from "pmtiles";
 import {
@@ -57,6 +57,12 @@ import {
 } from "./derived-geometry";
 import { ensureGeneratedImageHandler } from "./generated-images";
 import { prepareFillPattern } from "./fill-patterns";
+import {
+  getDynamicLayoutProperty,
+  getDynamicPaintProperty,
+  setDynamicLayoutProperty,
+  setDynamicPaintProperty,
+} from "./dynamic-style-property";
 import { prepareLineDecoration } from "./line-decorations";
 import {
   KML_ICON_URL_PROPERTY,
@@ -1684,8 +1690,8 @@ function syncVectorControlPointSymbology(
   // of the other rule-based paint overrides apply to control-owned layers.
   const radius = proportionalRadiusExpression(layer.style);
   if (radius) {
-    if (!styleValuesEqual(map.getPaintProperty?.(circleNativeId, "circle-radius"), radius)) {
-      map.setPaintProperty(circleNativeId, "circle-radius", radius);
+    if (!styleValuesEqual(getDynamicPaintProperty(map, circleNativeId, "circle-radius"), radius)) {
+      setDynamicPaintProperty(map, circleNativeId, "circle-radius", radius);
     }
     overriddenRadiusIdsFor(map).add(circleNativeId);
   } else {
@@ -1741,8 +1747,8 @@ function setExternalNativeLayerPaint(
 
   for (const [property, value] of Object.entries(paint)) {
     try {
-      if (!styleValuesEqual(map.getPaintProperty?.(nativeLayerId, property), value)) {
-        map.setPaintProperty(nativeLayerId, property, value);
+      if (!styleValuesEqual(getDynamicPaintProperty(map, nativeLayerId, property), value)) {
+        setDynamicPaintProperty(map, nativeLayerId, property, value);
       }
     } catch {
       // External controls can create heterogeneous style layers. Ignore paint
@@ -3426,15 +3432,15 @@ function ensureLayer(
   if (map.getLayer(id)) {
     if (spec.paint) {
       for (const [key, value] of Object.entries(spec.paint)) {
-        if (!styleValuesEqual(map.getPaintProperty?.(id, key), value)) {
-          map.setPaintProperty(id, key, value);
+        if (!styleValuesEqual(getDynamicPaintProperty(map, id, key), value)) {
+          setDynamicPaintProperty(map, id, key, value);
         }
       }
     }
     if (spec.layout) {
       for (const [key, value] of Object.entries(spec.layout)) {
-        if (!styleValuesEqual(map.getLayoutProperty?.(id, key), value)) {
-          map.setLayoutProperty(id, key, value);
+        if (!styleValuesEqual(getDynamicLayoutProperty(map, id, key), value)) {
+          setDynamicLayoutProperty(map, id, key, value);
         }
       }
     }
diff --git a/packages/map/src/map-controller.ts b/packages/map/src/map-controller.ts
index ffc956e1f..72eea8f31 100644
--- a/packages/map/src/map-controller.ts
+++ b/packages/map/src/map-controller.ts
@@ -18,7 +18,7 @@ import type {
 } from "@geolibre/core";
 import bbox from "@turf/bbox";
 import type { Feature, FeatureCollection, Geometry } from "geojson";
-import maplibregl from "maplibre-gl";
+import * as maplibregl from "maplibre-gl";
 import { LayerControl, type CustomLayerAdapter, type LayerState } from "maplibre-gl-layer-control";
 import { CollapsedAttributionControl } from "./collapsed-attribution-control";
 import {
@@ -50,6 +50,18 @@ import { getOfflineBasemapStyle, isOfflineBasemapSentinel } from "./protomaps-ba
 import { ResetBearingControl } from "./reset-bearing-control";
 import { MaptoolkitLogoControl } from "./maptoolkit-logo-control";
 import { TerrainControl, DEFAULT_TERRAIN_EXAGGERATION } from "./terrain-control";
+import { getDynamicPaintProperty, setDynamicPaintProperty } from "./dynamic-style-property";
+
+/**
+ * GeolocateControl is constructed through this indirection so tests can
+ * substitute a fake. Assigning over `maplibregl.GeolocateControl` is not an
+ * option: a MapLibre v6 ESM namespace is sealed and rejects assignment
+ * (`TypeError: Cannot assign to property 'GeolocateControl' of [object Module]`).
+ */
+export const geolocateControlFactory = {
+  create: (options: maplibregl.GeolocateControlOptions): maplibregl.GeolocateControl =>
+    new maplibregl.GeolocateControl(options),
+};
 
 const DEFAULT_PROJECTION: maplibregl.ProjectionSpecification = {
   type: "globe",
@@ -644,11 +656,11 @@ export class MapController {
       const props = OPACITY_PAINT_PROPERTIES[styleLayer.type] ?? [];
       for (const prop of props) {
         if (typeof durationMs === "number" && durationMs >= 0) {
-          this.map.setPaintProperty(nativeId, `${prop}-transition`, {
+          setDynamicPaintProperty(this.map, nativeId, `${prop}-transition`, {
             duration: durationMs,
           });
         }
-        this.map.setPaintProperty(nativeId, prop, clamped);
+        setDynamicPaintProperty(this.map, nativeId, prop, clamped);
       }
     }
   }
@@ -674,7 +686,7 @@ export class MapController {
           const styleLayer = this.map.getLayer(nativeId);
           if (!styleLayer) continue;
           for (const prop of OPACITY_PAINT_PROPERTIES[styleLayer.type] ?? []) {
-            this.map.setPaintProperty(nativeId, `${prop}-transition`, {
+            setDynamicPaintProperty(this.map, nativeId, `${prop}-transition`, {
               duration: 0,
             });
           }
@@ -1197,7 +1209,7 @@ export class MapController {
       this.basemapOriginalPaintValues.set(layerId, originalPaintValues);
     }
     if (!originalPaintValues.has(property)) {
-      originalPaintValues.set(property, this.map.getPaintProperty(layerId, property));
+      originalPaintValues.set(property, getDynamicPaintProperty(this.map, layerId, property));
     }
 
     const original = originalPaintValues.get(property);
@@ -1208,9 +1220,9 @@ export class MapController {
           ? original * this.basemapOpacity
           : this.basemapOpacity;
     try {
-      const current = this.map.getPaintProperty(layerId, property);
+      const current = getDynamicPaintProperty(this.map, layerId, property);
       if (styleValuesEqual(current, opacity)) return;
-      this.map.setPaintProperty(layerId, property, opacity);
+      setDynamicPaintProperty(this.map, layerId, property, opacity);
     } catch {
       // Some third-party custom style layers may not expose paint properties.
     }
@@ -2349,7 +2361,7 @@ export class MapController {
     if (!this.map || this.geolocateControl || !this.controlVisibility.geolocate) {
       return false;
     }
-    const control = new maplibregl.GeolocateControl({
+    const control = geolocateControlFactory.create({
       positionOptions: {
         enableHighAccuracy: true,
       },
diff --git a/packages/map/src/mapbox-style.ts b/packages/map/src/mapbox-style.ts
index c29122f3a..c9b0880dd 100644
--- a/packages/map/src/mapbox-style.ts
+++ b/packages/map/src/mapbox-style.ts
@@ -29,7 +29,7 @@
  * free of credential plumbing and makes a saved project self-contained.
  */
 
-import type maplibregl from "maplibre-gl";
+import type * as maplibregl from "maplibre-gl";
 
 /** Host serving both the style descriptors and the `mapbox://` redirect targets. */
 const MAPBOX_API_HOST = "api.mapbox.com";
diff --git a/packages/map/src/maptoolkit-logo-control.ts b/packages/map/src/maptoolkit-logo-control.ts
index 707218864..f8641a0d2 100644
--- a/packages/map/src/maptoolkit-logo-control.ts
+++ b/packages/map/src/maptoolkit-logo-control.ts
@@ -1,4 +1,4 @@
-import type maplibregl from "maplibre-gl";
+import type * as maplibregl from "maplibre-gl";
 
 /** Where the logo links, and the brand name used for the tooltip/aria label. */
 const MAPTOOLKIT_URL = "https://www.maptoolkit.org/";
diff --git a/packages/map/src/planetary-scale-control.ts b/packages/map/src/planetary-scale-control.ts
index 9107ec50b..18954e10e 100644
--- a/packages/map/src/planetary-scale-control.ts
+++ b/packages/map/src/planetary-scale-control.ts
@@ -5,7 +5,7 @@ import {
   scaleSpan,
   type MapScaleUnit,
 } from "@geolibre/core";
-import maplibregl from "maplibre-gl";
+import * as maplibregl from "maplibre-gl";
 
 // Re-exported so the nice-number rounding and unit conversion — now shared with
 // the Print Layout scale bar in `@geolibre/core` — can still be imported from
diff --git a/packages/map/src/protomaps-basemap.ts b/packages/map/src/protomaps-basemap.ts
index 983dd70bf..77149a7b5 100644
--- a/packages/map/src/protomaps-basemap.ts
+++ b/packages/map/src/protomaps-basemap.ts
@@ -8,7 +8,7 @@
 // via getOfflineBasemapStyle(). Glyphs and sprites default to app-bundled
 // assets (see scripts/fetch-basemaps-assets.mjs) so it renders fully offline.
 import { layers, namedFlavor } from "@protomaps/basemaps";
-import type maplibregl from "maplibre-gl";
+import type * as maplibregl from "maplibre-gl";
 
 /** The Protomaps basemap flavors we expose. */
 export const PROTOMAPS_FLAVORS = ["light", "dark", "white", "grayscale", "black"] as const;
diff --git a/packages/map/src/reset-bearing-control.ts b/packages/map/src/reset-bearing-control.ts
index cf48fdfb0..7b657a41f 100644
--- a/packages/map/src/reset-bearing-control.ts
+++ b/packages/map/src/reset-bearing-control.ts
@@ -1,4 +1,4 @@
-import type maplibregl from "maplibre-gl";
+import type * as maplibregl from "maplibre-gl";
 
 /**
  * Bearing/pitch below this magnitude is treated as "north-up and flat", so a
diff --git a/packages/map/src/terrain-control.ts b/packages/map/src/terrain-control.ts
index 0a2e26017..24b4fd666 100644
--- a/packages/map/src/terrain-control.ts
+++ b/packages/map/src/terrain-control.ts
@@ -1,4 +1,4 @@
-import type maplibregl from "maplibre-gl";
+import type * as maplibregl from "maplibre-gl";
 
 /**
  * Clicks landing within this window of the previous one are treated as a
diff --git a/packages/plugins/package.json b/packages/plugins/package.json
index 90acec81f..357c2ea3f 100644
--- a/packages/plugins/package.json
+++ b/packages/plugins/package.json
@@ -40,7 +40,7 @@
     "h5wasm": "^0.10.3",
     "jspdf": "^4.2.1",
     "mapillary-js": "^4.1.2",
-    "maplibre-gl": "^5.24.0",
+    "maplibre-gl": "^6.1.0",
     "maplibre-gl-3d-tiles": "^0.5.6",
     "maplibre-gl-basemap-control": "^0.13.0",
     "maplibre-gl-components": "^0.30.0",
diff --git a/packages/plugins/src/arcgis-maplibre.d.ts b/packages/plugins/src/arcgis-maplibre.d.ts
index a439abd80..9a9f9680f 100644
--- a/packages/plugins/src/arcgis-maplibre.d.ts
+++ b/packages/plugins/src/arcgis-maplibre.d.ts
@@ -1,5 +1,5 @@
 declare module "@esri/maplibre-arcgis" {
-  import type maplibregl from "maplibre-gl";
+  import type * as maplibregl from "maplibre-gl";
 
   export interface IHostedLayerOptions {
     attribution?: string;
diff --git a/packages/plugins/src/plugins/arcgis-layer.ts b/packages/plugins/src/plugins/arcgis-layer.ts
index d04db496d..e09092ed1 100644
--- a/packages/plugins/src/plugins/arcgis-layer.ts
+++ b/packages/plugins/src/plugins/arcgis-layer.ts
@@ -3,7 +3,7 @@
 import { DEFAULT_LAYER_STYLE, type GeoLibreLayer, useAppStore } from "@geolibre/core";
 import type { HostedLayer, VectorTileLayer } from "@esri/maplibre-arcgis";
 import type { FeatureCollection } from "geojson";
-import type maplibregl from "maplibre-gl";
+import type * as maplibregl from "maplibre-gl";
 import type { GeoLibreAppAPI } from "../types";
 
 export type ArcGISLayerType = "feature" | "vector-tile";
diff --git a/packages/plugins/src/plugins/geoagent-layer-sync.ts b/packages/plugins/src/plugins/geoagent-layer-sync.ts
index 2d93b504e..ee0fcd7f4 100644
--- a/packages/plugins/src/plugins/geoagent-layer-sync.ts
+++ b/packages/plugins/src/plugins/geoagent-layer-sync.ts
@@ -32,12 +32,19 @@ export type GeoAgentOverlayRecord = {
 /**
  * The slice of the GeoAgent tools surface the store -> GeoAgent sync needs.
  * Structural (rather than maplibre-gl types) so tests can pass fakes.
+ *
+ * Declared with method syntax, not function-typed properties: MapLibre v6 made
+ * `set/getPaintProperty` generic over `keyof AllPaintProperties`, and under
+ * `strictFunctionTypes` a function-typed property is checked contravariantly,
+ * so a real `Map` stops satisfying a `(id: string, property: string, ...)`
+ * slice. Methods are checked bivariantly, which accepts both a real map and a
+ * test fake.
  */
 export type GeoAgentSyncableTools = {
   map?: {
-    getLayer: (id: string) => { type: string } | undefined;
-    setLayoutProperty: (id: string, property: string, value: unknown) => unknown;
-    setPaintProperty: (id: string, property: string, value: unknown) => unknown;
+    getLayer(id: string): { type: string } | undefined;
+    setLayoutProperty(id: string, property: string, value: unknown): unknown;
+    setPaintProperty(id: string, property: string, value: unknown): unknown;
   };
   removeOverlay?: (name: string) => boolean;
 };
diff --git a/packages/plugins/src/plugins/maplibre-annotations.ts b/packages/plugins/src/plugins/maplibre-annotations.ts
index c04deef53..d3bb04953 100644
--- a/packages/plugins/src/plugins/maplibre-annotations.ts
+++ b/packages/plugins/src/plugins/maplibre-annotations.ts
@@ -1,6 +1,8 @@
 import { DEFAULT_LAYER_STYLE, type GeoLibreLayer, useAppStore } from "@geolibre/core";
 import type { Feature, FeatureCollection, Position } from "geojson";
-import maplibregl from "maplibre-gl";
+// A value (not type-only) namespace import: main added runtime use of
+// `maplibregl.LngLat`/`maplibregl.Marker` here, and v6 has no default export.
+import * as maplibregl from "maplibre-gl";
 import type { GeoLibreAppAPI, GeoLibreMapControlPosition, GeoLibrePlugin } from "../types";
 import { ANNOTATIONS_PLUGIN_ID } from "../plugin-ids";
 
diff --git a/packages/plugins/src/plugins/maplibre-components.ts b/packages/plugins/src/plugins/maplibre-components.ts
index f542f6d42..d5b993df5 100644
--- a/packages/plugins/src/plugins/maplibre-components.ts
+++ b/packages/plugins/src/plugins/maplibre-components.ts
@@ -17,7 +17,7 @@ import type { Layer } from "@deck.gl/core";
 import type { MapboxOverlay } from "@deck.gl/mapbox";
 import { RasterLayer, type RasterLayerProps } from "@developmentseed/deck.gl-raster";
 import { fromArrayBuffer } from "geotiff";
-import type maplibregl from "maplibre-gl";
+import type * as maplibregl from "maplibre-gl";
 import proj4 from "proj4";
 import type {
   AddVectorControl,
diff --git a/packages/plugins/src/plugins/maplibre-geo-editor.ts b/packages/plugins/src/plugins/maplibre-geo-editor.ts
index 8e2582a2e..d962704d0 100644
--- a/packages/plugins/src/plugins/maplibre-geo-editor.ts
+++ b/packages/plugins/src/plugins/maplibre-geo-editor.ts
@@ -1,7 +1,7 @@
 import { type GeoLibreLayer, lineWidthValue, styleValue, useAppStore } from "@geolibre/core";
 import { Geoman, defaultLayerStyles } from "@geoman-io/maplibre-geoman-free";
 import type { Feature, FeatureCollection } from "geojson";
-import type maplibregl from "maplibre-gl";
+import type * as maplibregl from "maplibre-gl";
 import { GeoEditor, type GeoEditorOptions } from "maplibre-gl-geo-editor";
 import {
   type EditedFeatureProperties,
@@ -123,6 +123,16 @@ let viewImportLoadCounter = 0;
 
 const GEOMAN_EDIT_SYNC_EVENTS = ["gm:dragend", "gm:editend", "gm:rotateend"] as const;
 
+/**
+ * MapLibre v6 narrowed the catch-all `Map#on`/`off` overload from `type: string`
+ * to `type: keyof MapEventType`, so Geoman's `gm:*` events no longer type-check
+ * even though the map dispatches them. Bind through this slice instead.
+ */
+interface ThirdPartyEventTarget {
+  on(type: string, listener: () => void): unknown;
+  off(type: string, listener: () => void): unknown;
+}
+
 export { GEO_EDITOR_PLUGIN_ID };
 
 export const maplibreGeoEditorPlugin: GeoLibrePlugin = {
@@ -239,14 +249,14 @@ function bindGeomanEditSync(map: maplibregl.Map): void {
   unbindGeomanEditSync();
   geomanEditSyncMap = map;
   for (const eventName of GEOMAN_EDIT_SYNC_EVENTS) {
-    map.on(eventName, handleGeomanEditSync);
+    (map as unknown as ThirdPartyEventTarget).on(eventName, handleGeomanEditSync);
   }
 }
 
 function unbindGeomanEditSync(): void {
   if (!geomanEditSyncMap) return;
   for (const eventName of GEOMAN_EDIT_SYNC_EVENTS) {
-    geomanEditSyncMap.off(eventName, handleGeomanEditSync);
+    (geomanEditSyncMap as unknown as ThirdPartyEventTarget).off(eventName, handleGeomanEditSync);
   }
   geomanEditSyncMap = null;
 }
@@ -1261,6 +1271,11 @@ function applyGeomanDisplayLayerOpacity(
   }
 }
 
+/** See the cast inside `setGeomanPaintProperty`. */
+interface DynamicPaintTarget {
+  setPaintProperty(layerId: string, property: string, value: unknown): void;
+}
+
 function setGeomanPaintProperty(
   map: maplibregl.Map,
   layerId: string,
@@ -1268,7 +1283,11 @@ function setGeomanPaintProperty(
   value: unknown,
 ): void {
   try {
-    map.setPaintProperty(layerId, property, value);
+    // v6 types setPaintProperty as generic over `keyof AllPaintProperties`, and
+    // these names are computed per layer type. Same rationale as
+    // `dynamic-style-property.ts` in @geolibre/map, which this package cannot
+    // import (plugins depends only on @geolibre/core).
+    (map as unknown as DynamicPaintTarget).setPaintProperty(layerId, property, value);
   } catch {
     // Geoman layers are rebuilt often and may not support every paint property.
   }
diff --git a/tests/hooks/maplibre-default-import-shim.mjs b/tests/hooks/maplibre-default-import-shim.mjs
new file mode 100644
index 000000000..13ae1c70f
--- /dev/null
+++ b/tests/hooks/maplibre-default-import-shim.mjs
@@ -0,0 +1,42 @@
+/**
+ * Node module-loader analogue of `apps/geolibre-desktop/vite-plugins/maplibre-default-import-shim.ts`.
+ *
+ * MapLibre v6 is ESM-only with no default export, so a third-party bundle
+ * compiled against v5's default export fails to instantiate under `node --test`:
+ *
+ *     SyntaxError: The requested module 'maplibre-gl' does not provide an
+ *     export named 'default'
+ *
+ * `tests/geo-editor-plugin.test.ts` hits this because the geo-editor plugin
+ * statically imports Geoman. The Vite shim cannot help here — `node --test`
+ * does not go through Vite — so the same rewrite is applied as a load hook.
+ *
+ * Temporary, and the list only ever shrinks: see opengeos/GeoLibre#1489
+ * (blocker 1). `tests/maplibre-shim-parity.test.ts` fails if this list and the
+ * Vite plugin's stop agreeing.
+ */
+
+/** Packages whose published ESM still default-imports maplibre-gl. */
+export const SHIMMED_PACKAGES = ["@esri/maplibre-arcgis", "@geoman-io/maplibre-geoman-free"];
+
+// Matches a default import of maplibre-gl in minified or unminified ESM:
+//   import Zt from"maplibre-gl"     import e from "maplibre-gl"
+const DEFAULT_IMPORT = /\bimport\s+([A-Za-z_$][\w$]*)\s+from\s*(["'])maplibre-gl\2/g;
+
+/** Rewrite default imports of maplibre-gl to namespace imports. */
+export function rewriteDefaultImports(source) {
+  return source.replace(
+    DEFAULT_IMPORT,
+    (_match, binding, quote) => `import * as ${binding} from ${quote}maplibre-gl${quote}`,
+  );
+}
+
+export async function load(url, context, nextLoad) {
+  const result = await nextLoad(url, context);
+  const shimmed = SHIMMED_PACKAGES.some((name) => url.includes(`/node_modules/${name}/`));
+  if (!shimmed || result.format !== "module" || result.source == null) return result;
+
+  const source = result.source.toString();
+  if (!source.includes("maplibre-gl")) return result;
+  return { ...result, source: rewriteDefaultImports(source) };
+}
diff --git a/tests/hooks/register-maplibre-shim.mjs b/tests/hooks/register-maplibre-shim.mjs
new file mode 100644
index 000000000..afac2af3a
--- /dev/null
+++ b/tests/hooks/register-maplibre-shim.mjs
@@ -0,0 +1,9 @@
+/**
+ * Registers the maplibre default-import load hook for `node --test`.
+ * Used via `node --import ./tests/hooks/register-maplibre-shim.mjs`, alongside
+ * tsx's own hooks — the two do not overlap (this one only rewrites published
+ * bundles under node_modules).
+ */
+import { register } from "node:module";
+
+register("./maplibre-default-import-shim.mjs", import.meta.url);
diff --git a/tests/map-controller.test.ts b/tests/map-controller.test.ts
index a996ba462..376aeb1b4 100644
--- a/tests/map-controller.test.ts
+++ b/tests/map-controller.test.ts
@@ -1,8 +1,12 @@
 import assert from "node:assert/strict";
 import { describe, it } from "node:test";
-import maplibregl from "maplibre-gl";
+import * as maplibregl from "maplibre-gl";
 import { DEFAULT_LAYER_STYLE, type GeoLibreLayer, type LayerStyle } from "@geolibre/core";
-import { createMapController, MapController } from "../packages/map/src/map-controller";
+import {
+  createMapController,
+  geolocateControlFactory,
+  MapController,
+} from "../packages/map/src/map-controller";
 
 // Internal shape of MapController we reach into to inject a fake map. The
 // controller only ever constructs a real maplibregl.Map through init(), which
@@ -1077,12 +1081,13 @@ function controllerWithGeolocate(): {
 const flush = () => new Promise((resolve) => setTimeout(resolve, 0));
 
 describe("MapController geolocate permission-denied recovery", () => {
-  const originalControl = maplibregl.GeolocateControl;
+  const originalCreate = geolocateControlFactory.create;
 
   function withStubbedControl(run: () => Promise<void>): Promise<void> {
-    (maplibregl as { GeolocateControl: unknown }).GeolocateControl = FakeGeolocateControl;
+    geolocateControlFactory.create = () =>
+      new FakeGeolocateControl() as unknown as maplibregl.GeolocateControl;
     return run().finally(() => {
-      (maplibregl as { GeolocateControl: unknown }).GeolocateControl = originalControl;
+      geolocateControlFactory.create = originalCreate;
     });
   }
 
diff --git a/tests/mapbox-style.test.ts b/tests/mapbox-style.test.ts
index 23fd514d4..11e422180 100644
--- a/tests/mapbox-style.test.ts
+++ b/tests/mapbox-style.test.ts
@@ -2,7 +2,7 @@ import assert from "node:assert/strict";
 import { describe, it } from "node:test";
 import { validateStyleMin } from "@maplibre/maplibre-gl-style-spec";
 import { getMapboxAccessToken } from "@geolibre/core";
-import type maplibregl from "maplibre-gl";
+import type * as maplibregl from "maplibre-gl";
 import {
   isMapboxStyleUrl,
   mapboxAccessTokenFromStyleUrl,
diff --git a/tests/maplibre-shim-parity.test.ts b/tests/maplibre-shim-parity.test.ts
new file mode 100644
index 000000000..36d5f7775
--- /dev/null
+++ b/tests/maplibre-shim-parity.test.ts
@@ -0,0 +1,58 @@
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import { describe, it } from "node:test";
+import { fileURLToPath } from "node:url";
+import { SHIMMED_PACKAGES } from "./hooks/maplibre-default-import-shim.mjs";
+
+/**
+ * Two shims rewrite `import X from "maplibre-gl"` to a namespace import inside
+ * third-party bundles that still target v5: a Vite plugin for the app build and
+ * a Node load hook for `node --test` (Vite cannot reach the test runner). They
+ * must cover the same packages — a package shimmed in only one place fails in
+ * whichever environment was missed, and only there.
+ *
+ * Both are temporary. When `@esri/maplibre-arcgis` or
+ * `@geoman-io/maplibre-geoman-free` ship v6-compatible builds, drop the package
+ * from both lists together. See opengeos/GeoLibre#1489 (blocker 1).
+ */
+const VITE_PLUGIN = fileURLToPath(
+  new URL("../apps/geolibre-desktop/vite-plugins/maplibre-default-import-shim.ts", import.meta.url),
+);
+
+function shimmedPackagesInVitePlugin(): string[] {
+  const source = readFileSync(VITE_PLUGIN, "utf8");
+  const list = /const SHIMMED_PACKAGES = \[([^\]]*)\]/.exec(source);
+  assert.ok(list, "SHIMMED_PACKAGES array not found in the Vite plugin");
+  return [...list[1].matchAll(/"([^"]+)"/g)].map((match) => match[1]);
+}
+
+describe("maplibre default-import shims", () => {
+  it("cover the same packages in the Vite build and the Node test runner", () => {
+    assert.deepEqual(shimmedPackagesInVitePlugin(), [...SHIMMED_PACKAGES]);
+  });
+
+  it("rewrites the default import forms both packages actually publish", async () => {
+    const { rewriteDefaultImports } = await import("./hooks/maplibre-default-import-shim.mjs");
+
+    // @esri/maplibre-arcgis (minified, no space before the specifier — the
+    // rewrite normalizes that to one space, which is still valid ESM).
+    assert.equal(
+      rewriteDefaultImports('import Zt from"maplibre-gl"'),
+      'import * as Zt from "maplibre-gl"',
+    );
+    // @geoman-io/maplibre-geoman-free (spaced).
+    assert.equal(
+      rewriteDefaultImports('import e from "maplibre-gl"'),
+      'import * as e from "maplibre-gl"',
+    );
+    // Named and namespace imports are already v6-safe and must be left alone.
+    assert.equal(
+      rewriteDefaultImports('import { Popup } from "maplibre-gl"'),
+      'import { Popup } from "maplibre-gl"',
+    );
+    assert.equal(
+      rewriteDefaultImports('import * as ml from "maplibre-gl"'),
+      'import * as ml from "maplibre-gl"',
+    );
+  });
+});
diff --git a/tests/package.json b/tests/package.json
new file mode 100644
index 000000000..3dbc1ca59
--- /dev/null
+++ b/tests/package.json
@@ -0,0 +1,3 @@
+{
+  "type": "module"
+}
diff --git a/tests/terrain-control.test.ts b/tests/terrain-control.test.ts
index 377e755f0..fe3db57a9 100644
--- a/tests/terrain-control.test.ts
+++ b/tests/terrain-control.test.ts
@@ -1,6 +1,6 @@
 import assert from "node:assert/strict";
 import { afterEach, describe, it, mock } from "node:test";
-import type maplibregl from "maplibre-gl";
+import type * as maplibregl from "maplibre-gl";
 import { TerrainControl } from "../packages/map/src/terrain-control";
 
 // TerrainControl.onAdd builds DOM nodes; node:test has no DOM, so stand up a