diff --git a/client/scripts/size-baseline.json b/client/scripts/size-baseline.json
index 5bf49f75a..6ad44b8a4 100644
--- a/client/scripts/size-baseline.json
+++ b/client/scripts/size-baseline.json
@@ -7,7 +7,7 @@
   "src/components/Budget/CostsPanel.tsx": 1816,
   "src/components/Map/MapView.tsx": 1401,
   "src/components/Map/MapViewGL.test.tsx": 2920,
-  "src/components/Map/MapViewGL.tsx": 2296,
+  "src/components/Map/MapViewGL.tsx": 2293,
   "src/components/Map/RouteCalculator.ts": 1195,
   "src/components/PDF/TripPDF.tsx": 1082,
   "src/components/Planner/DayDetailPanel.test.tsx": 2333,
diff --git a/client/src/components/Map/MapViewGL.test.tsx b/client/src/components/Map/MapViewGL.test.tsx
index db80c2909..6a1b4a0ac 100644
--- a/client/src/components/Map/MapViewGL.test.tsx
+++ b/client/src/components/Map/MapViewGL.test.tsx
@@ -257,6 +257,7 @@ beforeEach(() => {
   glMap.querySourceFeatures.mockReturnValue([])
   glMap.getCanvas.mockImplementation(() => document.createElement('canvas'))
   glMap.getBearing.mockReturnValue(0)
+  glMap.getZoom.mockReturnValue(10)
   glMap.queryTerrainElevation.mockReturnValue(null)
   // A busy style, a refused source and a custom layer list are each set by one test
   // for the case it covers. Put back here, or every test after it would silently run
@@ -1575,7 +1576,6 @@ describe('MapViewGL', () => {
     const list = calls[calls.length - 1][0]
     act(() => { list.querySelectorAll('button')[1].click() })
     expect(onPoiClick).toHaveBeenCalledWith(other)
-    vi.mocked(glMap.getZoom).mockReturnValue(10)
   })
 
   const pinGlyph = (Icon: LucideIcon) => renderIconMarkup(React.createElement(Icon, { size: 13, color: 'white', strokeWidth: 2.5 }))
@@ -2215,14 +2215,12 @@ describe('MapViewGL', () => {
     expect((window as any).__trek_map).toBeUndefined()
   })
 
-  it('FE-COMP-MAPVIEWGL-059: pan and zoom report the visible bbox for the POI explore pill, with the zoom on the raster tile scale', async () => {
+  it('FE-COMP-MAPVIEWGL-059: pan and zoom report the visible bbox and tile zoom for the POI explore pill', async () => {
     const onViewportChange = vi.fn()
-    vi.mocked(glMap.getZoom).mockReturnValue(10)
     render(<MapViewGL places={[]} fitKey={1} onViewportChange={onViewportChange} />)
     await act(async () => {})
 
     act(() => { mapHandler('moveend')() })
-    // The GL engine counts on 512 px tiles; a raster tile's zoom is one step further in.
     expect(onViewportChange).toHaveBeenCalledWith({ south: 0, west: 0, north: 1, east: 1 }, 11)
   })
 
diff --git a/client/src/components/Map/MapViewGL.tsx b/client/src/components/Map/MapViewGL.tsx
index a4121a45b..0acd2a492 100644
--- a/client/src/components/Map/MapViewGL.tsx
+++ b/client/src/components/Map/MapViewGL.tsx
@@ -8,7 +8,8 @@ import { renderIconMarkup } from '../../utils/iconMarkup'
 import type mapboxgl from 'mapbox-gl'
 import { useSettingsStore } from '../../store/settingsStore'
 import { useTranslation } from '../../i18n/TranslationContext'
-import { applyBaseLayer, rasterTileZoom } from './glRasterLayers'
+import { applyBaseLayer } from './glRasterLayers'
+import { reportGlViewport } from './glViewport'
 import { isTourLayerHit, useTourMapLayersGL } from './mapRasterOverlay'
 import { MapLayerSwitcher, TourMapLayerSwitcher, MAP_LAYER_SWITCHER_INSET, type BaseLayer, type TourBaseLayer } from './MapLayerSwitcher'
 import { MapLockPill } from './MapLockPill'
@@ -1432,15 +1433,8 @@ export function MapViewGL({
       if (isTourLayerHit(map, e.point)) return // a picked via ferrata or paddle obstacle opens its card instead
       onClickRefs.current.map?.({ latlng: { lat: e.lngLat.lat, lng: e.lngLat.lng } })
     })
-    // Emit the viewport bbox (pan/zoom + once on first idle) so the POI-explore
-    // pill can fetch OSM places for the visible area, with the zoom on the raster tile scale.
-    const emitViewport = () => {
-      const b = map.getBounds()
-      onViewportChangeRef.current?.(
-        { south: b.getSouth(), west: b.getWest(), north: b.getNorth(), east: b.getEast() },
-        rasterTileZoom(map.getZoom()),
-      )
-    }
+    // Emit the viewport (pan/zoom + once on first idle) for the POI-explore pill.
+    const emitViewport = () => reportGlViewport(map, onViewportChangeRef.current)
     map.on('moveend', emitViewport)
     map.once('idle', emitViewport)
     // Clear the hover card (and the anchored POI popup) as soon as the camera
diff --git a/client/src/components/Map/glViewport.test.ts b/client/src/components/Map/glViewport.test.ts
new file mode 100644
index 000000000..b6294bdee
--- /dev/null
+++ b/client/src/components/Map/glViewport.test.ts
@@ -0,0 +1,35 @@
+import { describe, expect, it, vi } from 'vitest';
+import { reportGlViewport } from './glViewport';
+
+/** A GL map showing the given box at the given zoom, or no box yet. */
+function fakeMap(zoom: number, box: { south: number; west: number; north: number; east: number } | null) {
+  const bounds = box && {
+    getSouth: () => box.south,
+    getWest: () => box.west,
+    getNorth: () => box.north,
+    getEast: () => box.east,
+  };
+  return { getBounds: () => bounds, getZoom: () => zoom };
+}
+
+describe('reportGlViewport', () => {
+  it('reports the visible box with the zoom on the raster tile scale', () => {
+    const report = vi.fn();
+    reportGlViewport(fakeMap(10, { south: 47, west: 11, north: 48, east: 12 }), report);
+    // The GL engine counts on 512 px tiles; a raster tile's zoom is one step further in.
+    expect(report).toHaveBeenCalledWith({ south: 47, west: 11, north: 48, east: 12 }, 11);
+  });
+
+  it('says nothing while the map has no bounds yet', () => {
+    const report = vi.fn();
+    reportGlViewport(fakeMap(10, null), report);
+    expect(report).not.toHaveBeenCalled();
+  });
+
+  it('asks nothing of the map when no one listens', () => {
+    const map = fakeMap(10, { south: 47, west: 11, north: 48, east: 12 });
+    const getZoom = vi.spyOn(map, 'getZoom');
+    reportGlViewport(map, undefined);
+    expect(getZoom).not.toHaveBeenCalled();
+  });
+});
diff --git a/client/src/components/Map/glViewport.ts b/client/src/components/Map/glViewport.ts
new file mode 100644
index 000000000..f9c7464d6
--- /dev/null
+++ b/client/src/components/Map/glViewport.ts
@@ -0,0 +1,21 @@
+import { rasterTileZoom } from './glRasterLayers';
+import type { MapViewProps } from './mapViewContract';
+
+/** Enough of a GL map to say what it shows: its bounds and its zoom. */
+interface ViewportSource {
+  getBounds(): { getSouth(): number; getWest(): number; getNorth(): number; getEast(): number } | null;
+  getZoom(): number;
+}
+
+/**
+ * Tells the page what a GL map shows, so the POI explore pill can fetch the
+ * OSM places of the visible area: its bounds, and its zoom on the raster tile
+ * scale Leaflet reports too, so both maps ask for the same places at the
+ * same view. A map without bounds yet says nothing.
+ */
+export function reportGlViewport(map: ViewportSource, report: MapViewProps['onViewportChange']): void {
+  const bounds = map.getBounds();
+  if (!report || !bounds) return;
+  const bbox = { south: bounds.getSouth(), west: bounds.getWest(), north: bounds.getNorth(), east: bounds.getEast() };
+  report(bbox, rasterTileZoom(map.getZoom()));
+}