diff --git a/src/features/online-board/components/OnlineBoardFilter.test.tsx b/src/features/online-board/components/OnlineBoardFilter.test.tsx
index 00b15abb..35ddbd71 100644
--- a/src/features/online-board/components/OnlineBoardFilter.test.tsx
+++ b/src/features/online-board/components/OnlineBoardFilter.test.tsx
@@ -249,6 +249,48 @@ describe("OnlineBoardFilter – time slider 1h minimum gap per TZ §4.1.9 Tables
   });
 });
 
+describe("OnlineBoardFilter – submit lock", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    _sliderOnChange = null;
+  });
+
+  it("keeps the same submitted route search locked", () => {
+    render(
+      <OnlineBoardFilter
+        initialTab="route"
+        initialDeparture="MOW"
+        initialArrival="LED"
+        initialDate="20260515"
+      />,
+    );
+
+    fireEvent.submit(screen.getByTestId("search-form"));
+
+    expect(screen.getByTestId("search-submit")).toHaveProperty("disabled", true);
+  });
+
+  it("unlocks route search after the user changes the time range", () => {
+    render(
+      <OnlineBoardFilter
+        initialTab="route"
+        initialDeparture="MOW"
+        initialArrival="LED"
+        initialDate="20260515"
+      />,
+    );
+
+    fireEvent.submit(screen.getByTestId("search-form"));
+    expect(screen.getByTestId("search-submit")).toHaveProperty("disabled", true);
+
+    act(() => {
+      _sliderOnChange?.({ value: [600, 1440] });
+    });
+
+    expect(screen.getByTestId("search-submit")).toHaveProperty("disabled", false);
+  });
+});
+
 describe("OnlineBoardFilter – flight-number validation per TZ §4.1.9.3", () => {
   beforeEach(() => {
     vi.clearAllMocks();
diff --git a/src/features/online-board/components/OnlineBoardFilter.tsx b/src/features/online-board/components/OnlineBoardFilter.tsx
index a6311a49..1ab42cb2 100644
--- a/src/features/online-board/components/OnlineBoardFilter.tsx
+++ b/src/features/online-board/components/OnlineBoardFilter.tsx
@@ -254,6 +254,7 @@ export const OnlineBoardFilter: FC<OnlineBoardFilterProps> = ({
   // Value is the timestamp when the lock expires (or 0 if unlocked).
   // The 30-second constant is intentionally hardcoded (not configurable).
   const [submitLockedUntil, setSubmitLockedUntil] = useState(0);
+  const [lockedSearchSignature, setLockedSearchSignature] = useState<string | null>(null);
   const [now, setNow] = useState(() => Date.now());
   // Tick every second while the lock is active so the disabled state
   // updates reactively.
@@ -262,9 +263,38 @@ export const OnlineBoardFilter: FC<OnlineBoardFilterProps> = ({
     const id = setTimeout(() => setNow(Date.now()), 1000);
     return () => clearTimeout(id);
   }, [submitLockedUntil, now]);
+  const flightSearchSignature = useMemo(() => {
+    const dateParam = dateToYyyymmdd(flightDate ?? todayDate);
+    return [
+      "flight",
+      flightNumber.trim(),
+      dateParam,
+    ].join("|");
+  }, [flightNumber, flightDate, todayDate]);
+
+  const routeSearchSignature = useMemo(() => {
+    const dateParam = dateToYyyymmdd(routeDate ?? todayDate);
+    const timePart =
+      timeRange[0] !== 0 || timeRange[1] !== 1440
+        ? `${minutesToHhmm(timeRange[0])}-${minutesToHhmm(timeRange[1])}`
+        : "full-day";
+    return [
+      "route",
+      routeDepartureCode.trim().toUpperCase(),
+      routeArrivalCode.trim().toUpperCase(),
+      dateParam,
+      timePart,
+    ].join("|");
+  }, [routeDepartureCode, routeArrivalCode, routeDate, timeRange, todayDate]);
+
+  const activeSearchSignature =
+    activeTab === "flight" ? flightSearchSignature : routeSearchSignature;
   const isSubmitLocked = useMemo(
-    () => submitLockedUntil > 0 && now < submitLockedUntil,
-    [submitLockedUntil, now],
+    () =>
+      submitLockedUntil > 0 &&
+      now < submitLockedUntil &&
+      lockedSearchSignature === activeSearchSignature,
+    [submitLockedUntil, now, lockedSearchSignature, activeSearchSignature],
   );
 
   // Swap the Calendar input's display text to "Сегодня" / "Завтра" per
@@ -369,13 +399,14 @@ export const OnlineBoardFilter: FC<OnlineBoardFilterProps> = ({
       });
 
       // Lock submit for 30 seconds (§4.1.10 — hardcoded, not configurable)
+      setLockedSearchSignature(flightSearchSignature);
       setSubmitLockedUntil(Date.now() + 30_000);
       setNow(Date.now());
 
       const url = buildOnlineBoardUrl({ type: "flight", carrier, flightNumber: num, date: dateParam });
       void navigate(`/${locale}/${url}`);
     },
-    [flightNumber, flightDate, navigate, locale, isSubmitLocked],
+    [flightNumber, flightDate, navigate, locale, isSubmitLocked, flightSearchSignature],
   );
 
   const handleRouteSubmit = useCallback(
@@ -448,11 +479,12 @@ export const OnlineBoardFilter: FC<OnlineBoardFilterProps> = ({
         url = buildOnlineBoardUrl({ type: "route", departure: depCode, arrival: arrCode, date: dateParam, ...timeExtras });
       }
       // Lock submit for 30 seconds (§4.1.10 — hardcoded, not configurable)
+      setLockedSearchSignature(routeSearchSignature);
       setSubmitLockedUntil(Date.now() + 30_000);
       setNow(Date.now());
       void navigate(`/${locale}/${url}`);
     },
-    [routeDepartureCode, routeArrivalCode, routeDate, timeRange, navigate, locale, isSubmitLocked],
+    [routeDepartureCode, routeArrivalCode, routeDate, timeRange, navigate, locale, isSubmitLocked, routeSearchSignature],
   );
 
   return (
diff --git a/tests/e2e/onlineboard-time-filter.spec.ts b/tests/e2e/onlineboard-time-filter.spec.ts
index b080f16a..c9bdf7ae 100644
--- a/tests/e2e/onlineboard-time-filter.spec.ts
+++ b/tests/e2e/onlineboard-time-filter.spec.ts
@@ -87,5 +87,18 @@ test.describe("Onlineboard time-range filter (TIRREDESIGN-11)", () => {
 
     // URL must have grown a time suffix.
     await expect(page).toHaveURL(/\/onlineboard\/route\/MOW-LED-\d{8}-\d{8}/);
+
+    const firstFilteredUrl = page.url();
+
+    await slider.click({
+      position: { x: sliderBox.width * 0.75, y: sliderBox.height / 2 },
+    });
+    await expect(page.locator('[data-testid="search-submit"]')).toBeEnabled();
+    await page.locator('[data-testid="search-submit"]').click();
+    await page.waitForURL(
+      (url) =>
+        url.href !== firstFilteredUrl &&
+        /\/onlineboard\/route\/MOW-LED-\d{8}-\d{8}$/.test(url.pathname),
+    );
   });
 });