diff --git a/apps/planner/app/components/PlannerMap.tsx b/apps/planner/app/components/PlannerMap.tsx
index cc9789c..b194a0d 100644
--- a/apps/planner/app/components/PlannerMap.tsx
+++ b/apps/planner/app/components/PlannerMap.tsx
@@ -10,6 +10,7 @@ import { parseGpxAsync, extractWaypoints } from "@trails-cool/gpx";
 import { isOvernight } from "~/lib/overnight";
 import { setOvernight } from "~/lib/overnight";
 import { usePois } from "~/lib/use-pois";
+import { useProfileDefaults } from "~/lib/use-profile-defaults";
 import { snapToPoi } from "~/lib/poi-snap";
 import { Z_CURSOR, Z_WAYPOINT, Z_WAYPOINT_HIGHLIGHTED, Z_HIGHLIGHT } from "~/lib/z-index";
 import { NoGoAreaLayer } from "./NoGoAreaLayer";
@@ -278,6 +279,7 @@ export function PlannerMap({ yjs, onRouteRequest, highlightPosition, highlighted
   const { t } = useTranslation("planner");
   const [waypoints, setWaypoints] = useState<WaypointData[]>([]);
   const poiState = usePois();
+  useProfileDefaults(yjs, poiState);
   const [draggingOver, setDraggingOver] = useState(false);
   const dragCounterRef = useRef(0);
   const [routeCoordinates, setRouteCoordinates] = useState<[number, number, number][] | null>(null);
diff --git a/apps/planner/app/lib/use-pois.ts b/apps/planner/app/lib/use-pois.ts
index 5aacb56..926b498 100644
--- a/apps/planner/app/lib/use-pois.ts
+++ b/apps/planner/app/lib/use-pois.ts
@@ -15,7 +15,7 @@ export interface PoiState {
   pois: Poi[];
   status: PoiStatus;
   enabledCategories: string[];
-  setEnabledCategories: (ids: string[]) => void;
+  setEnabledCategories: React.Dispatch<React.SetStateAction<string[]>>;
   toggleCategory: (id: string) => void;
   refresh: (bbox: BBox, zoom: number) => void;
 }
diff --git a/apps/planner/app/lib/use-profile-defaults.ts b/apps/planner/app/lib/use-profile-defaults.ts
new file mode 100644
index 0000000..f591bb1
--- /dev/null
+++ b/apps/planner/app/lib/use-profile-defaults.ts
@@ -0,0 +1,45 @@
+import { useEffect, useRef } from "react";
+import type { YjsState } from "./use-yjs.ts";
+import type { PoiState } from "./use-pois.ts";
+import { getCategoriesForProfile } from "./poi-categories.ts";
+
+/**
+ * Auto-enable relevant POI categories when the routing profile changes.
+ * Only triggers on explicit profile changes (not initial load).
+ */
+export function useProfileDefaults(yjs: YjsState | null, poiState: PoiState): void {
+  const initializedRef = useRef(false);
+  const prevProfileRef = useRef<string | null>(null);
+
+  useEffect(() => {
+    if (!yjs) return;
+
+    const handleChange = () => {
+      const profile = yjs.routeData.get("profile") as string | undefined;
+      if (!profile) return;
+
+      // Skip initial load — respect existing state
+      if (!initializedRef.current) {
+        initializedRef.current = true;
+        prevProfileRef.current = profile;
+        return;
+      }
+
+      // Only act on actual profile changes
+      if (profile === prevProfileRef.current) return;
+      prevProfileRef.current = profile;
+
+      // Auto-enable POI categories for this profile
+      const defaultCategories = getCategoriesForProfile(profile);
+      if (defaultCategories.length > 0) {
+        poiState.setEnabledCategories((prev: string[]) => {
+          const merged = new Set([...prev, ...defaultCategories]);
+          return [...merged];
+        });
+      }
+    };
+
+    yjs.routeData.observe(handleChange);
+    return () => yjs.routeData.unobserve(handleChange);
+  }, [yjs, poiState.setEnabledCategories]);
+}
diff --git a/openspec/changes/osm-overlays/tasks.md b/openspec/changes/osm-overlays/tasks.md
index 8bb689c..81df7ea 100644
--- a/openspec/changes/osm-overlays/tasks.md
+++ b/openspec/changes/osm-overlays/tasks.md
@@ -47,9 +47,9 @@
 
 ## 8. Profile-Aware Defaults
 
-- [ ] 8.1 Define profile-to-overlay mapping (cycling → waymarked-cycling + bike POIs, hiking → waymarked-hiking + shelter + viewpoints, MTB → waymarked-mtb + bike POIs)
-- [ ] 8.2 Auto-enable mapped overlays on routing profile change (update Yjs arrays)
-- [ ] 8.3 Only auto-enable on explicit profile change, not on initial page load (respect existing Yjs state)
+- [x] 8.1 Define profile-to-overlay mapping (cycling → waymarked-cycling + bike POIs, hiking → waymarked-hiking + shelter + viewpoints, MTB → waymarked-mtb + bike POIs)
+- [x] 8.2 Auto-enable mapped overlays on routing profile change (update Yjs arrays)
+- [x] 8.3 Only auto-enable on explicit profile change, not on initial page load (respect existing Yjs state)
 
 ## 9. i18n