diff --git a/src/features/online-board/components/OnlineBoardDetailsPage.tsx b/src/features/online-board/components/OnlineBoardDetailsPage.tsx
index 0937cc75..f0133f33 100644
--- a/src/features/online-board/components/OnlineBoardDetailsPage.tsx
+++ b/src/features/online-board/components/OnlineBoardDetailsPage.tsx
@@ -401,7 +401,7 @@ export const OnlineBoardDetailsPage: FC<OnlineBoardDetailsPageProps> = ({
 
   // Live updates via SignalR
   const { flight: liveFlight, connectionStatus } = useLiveFlightDetails(
-    flight?.flightId ?? flightId,
+    flight?.flightId ?? null,
     flight,
     refresh,
   );
diff --git a/src/features/online-board/hooks/useLiveFlightDetails.test.ts b/src/features/online-board/hooks/useLiveFlightDetails.test.ts
index 739709ba..811ee05e 100644
--- a/src/features/online-board/hooks/useLiveFlightDetails.test.ts
+++ b/src/features/online-board/hooks/useLiveFlightDetails.test.ts
@@ -240,6 +240,23 @@ describe("useLiveFlightDetails", () => {
     expect(result.current.flight).toBeNull();
   });
 
+  it("does not subscribe before the API flight id is available", async () => {
+    const { hub, conn } = installMockHub(HUB_URL);
+    const subscribeSpy = vi.spyOn(conn, "subscribe");
+
+    const { result } = renderHook(() =>
+      useLiveFlightDetails(null, null),
+    );
+
+    await act(async () => {
+      await vi.runAllTimersAsync();
+    });
+
+    expect(result.current.connectionStatus).toBe("idle");
+    expect(subscribeSpy).not.toHaveBeenCalled();
+    expect(hub.invoke).not.toHaveBeenCalled();
+  });
+
   it("subscribes to Angular TrackerHub refresh and invokes Subscribe", async () => {
     const { hub } = installMockHub(HUB_URL);
     const id: IParsedFlightId = {
diff --git a/src/features/online-board/hooks/useLiveFlightDetails.ts b/src/features/online-board/hooks/useLiveFlightDetails.ts
index b74b7369..c4b28435 100644
--- a/src/features/online-board/hooks/useLiveFlightDetails.ts
+++ b/src/features/online-board/hooks/useLiveFlightDetails.ts
@@ -34,6 +34,13 @@ export interface UseLiveFlightDetailsResult {
 
 type LiveFlightId = IParsedFlightId | IFlightId;
 
+const DISABLED_ID: LiveFlightId = {
+  carrier: "",
+  flightNumber: "",
+  suffix: "",
+  date: "",
+};
+
 export function buildFlightChannelKey(id: LiveFlightId): string {
   return `flight:${id.carrier}${id.flightNumber}${id.suffix ?? ""}@${id.date}`;
 }
@@ -48,13 +55,15 @@ export function buildTrackerFlightSubscriptionKey(id: LiveFlightId): string {
 // ---------------------------------------------------------------------------
 
 export function useLiveFlightDetails(
-  id: LiveFlightId,
+  id: LiveFlightId | null,
   initialFlight: ISimpleFlight | null,
   onRefresh?: () => void,
 ): UseLiveFlightDetailsResult {
+  const env = getEnv();
+  const effectiveId = id ?? DISABLED_ID;
   const config = useMemo<UseLiveFlightsConfig<LiveFlightId>>(
     () => ({
-      hubUrl: getEnv().SIGNALR_HUB_URL,
+      hubUrl: id ? env.SIGNALR_HUB_URL : "",
       channelKey: buildFlightChannelKey,
       subscription: {
         eventName: "Refresh",
@@ -67,7 +76,7 @@ export function useLiveFlightDetails(
         return undefined;
       },
     }),
-    [onRefresh],
+    [env.SIGNALR_HUB_URL, id, onRefresh],
   );
 
   // useLiveFlights expects an array — wrap/unwrap the single flight
@@ -79,7 +88,7 @@ export function useLiveFlightDetails(
   const { data, connectionStatus } = useLiveFlights<
     LiveFlightId,
     ISimpleFlight
-  >(id, initialData, config);
+  >(effectiveId, initialData, config);
 
   const flight = data[0] ?? null;