diff --git a/docs/reference/functions/AuthCheck.md b/docs/reference/functions/AuthCheck.md
index 9bedbb15..91702f7b 100644
--- a/docs/reference/functions/AuthCheck.md
+++ b/docs/reference/functions/AuthCheck.md
@@ -8,7 +8,7 @@
 
 > **AuthCheck**(`__namedParameters`): `Element`
 
-Defined in: [src/auth.tsx:247](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L247)
+Defined in: [src/auth.tsx:257](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L257)
 
 ## Parameters
 
diff --git a/docs/reference/functions/ClaimsCheck.md b/docs/reference/functions/ClaimsCheck.md
index 8fa527d8..5138d974 100644
--- a/docs/reference/functions/ClaimsCheck.md
+++ b/docs/reference/functions/ClaimsCheck.md
@@ -8,7 +8,7 @@
 
 > **ClaimsCheck**(`__namedParameters`): `Element`
 
-Defined in: [src/auth.tsx:203](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L203)
+Defined in: [src/auth.tsx:213](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L213)
 
 ## Parameters
 
diff --git a/docs/reference/functions/useIdTokenResult.md b/docs/reference/functions/useIdTokenResult.md
index caa6c9d5..a8e573dd 100644
--- a/docs/reference/functions/useIdTokenResult.md
+++ b/docs/reference/functions/useIdTokenResult.md
@@ -8,7 +8,7 @@
 
 > **useIdTokenResult**(`user`, `forceRefresh?`, `options?`): [`ObservableStatus`](../type-aliases/ObservableStatus.md)\<`IdTokenResult`\>
 
-Defined in: [src/auth.tsx:31](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L31)
+Defined in: [src/auth.tsx:41](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L41)
 
 ## Parameters
 
diff --git a/docs/reference/functions/useSigninCheck.md b/docs/reference/functions/useSigninCheck.md
index d8a7c15d..928d22e5 100644
--- a/docs/reference/functions/useSigninCheck.md
+++ b/docs/reference/functions/useSigninCheck.md
@@ -8,7 +8,7 @@
 
 > **useSigninCheck**(`options?`): [`ObservableStatus`](../type-aliases/ObservableStatus.md)\<[`SigninCheckResult`](../type-aliases/SigninCheckResult.md)\>
 
-Defined in: [src/auth.tsx:124](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L124)
+Defined in: [src/auth.tsx:134](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L134)
 
 Subscribe to the signed-in status of a user.
 
diff --git a/docs/reference/interfaces/AuthCheckProps.md b/docs/reference/interfaces/AuthCheckProps.md
index d24c0e50..37e7b895 100644
--- a/docs/reference/interfaces/AuthCheckProps.md
+++ b/docs/reference/interfaces/AuthCheckProps.md
@@ -6,7 +6,7 @@
 
 # Interface: AuthCheckProps
 
-Defined in: [src/auth.tsx:42](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L42)
+Defined in: [src/auth.tsx:52](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L52)
 
 ## Properties
 
@@ -14,7 +14,7 @@ Defined in: [src/auth.tsx:42](https://github.com/FirebaseExtended/reactfire/blob
 
 > **children**: `ReactNode`
 
-Defined in: [src/auth.tsx:44](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L44)
+Defined in: [src/auth.tsx:54](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L54)
 
 ***
 
@@ -22,7 +22,7 @@ Defined in: [src/auth.tsx:44](https://github.com/FirebaseExtended/reactfire/blob
 
 > **fallback**: `ReactNode`
 
-Defined in: [src/auth.tsx:43](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L43)
+Defined in: [src/auth.tsx:53](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L53)
 
 ***
 
@@ -30,4 +30,4 @@ Defined in: [src/auth.tsx:43](https://github.com/FirebaseExtended/reactfire/blob
 
 > `optional` **requiredClaims?**: `Object`
 
-Defined in: [src/auth.tsx:45](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L45)
+Defined in: [src/auth.tsx:55](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L55)
diff --git a/docs/reference/interfaces/ClaimCheckErrors.md b/docs/reference/interfaces/ClaimCheckErrors.md
index 6e4bc87d..470ca5ab 100644
--- a/docs/reference/interfaces/ClaimCheckErrors.md
+++ b/docs/reference/interfaces/ClaimCheckErrors.md
@@ -6,7 +6,7 @@
 
 # Interface: ClaimCheckErrors
 
-Defined in: [src/auth.tsx:55](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L55)
+Defined in: [src/auth.tsx:65](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L65)
 
 ## Indexable
 
diff --git a/docs/reference/interfaces/ClaimsCheckProps.md b/docs/reference/interfaces/ClaimsCheckProps.md
index 9ea853a1..4d39e79b 100644
--- a/docs/reference/interfaces/ClaimsCheckProps.md
+++ b/docs/reference/interfaces/ClaimsCheckProps.md
@@ -6,7 +6,7 @@
 
 # Interface: ClaimsCheckProps
 
-Defined in: [src/auth.tsx:48](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L48)
+Defined in: [src/auth.tsx:58](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L58)
 
 ## Properties
 
@@ -14,7 +14,7 @@ Defined in: [src/auth.tsx:48](https://github.com/FirebaseExtended/reactfire/blob
 
 > **children**: `ReactNode`
 
-Defined in: [src/auth.tsx:51](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L51)
+Defined in: [src/auth.tsx:61](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L61)
 
 ***
 
@@ -22,7 +22,7 @@ Defined in: [src/auth.tsx:51](https://github.com/FirebaseExtended/reactfire/blob
 
 > **fallback**: `ReactNode`
 
-Defined in: [src/auth.tsx:50](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L50)
+Defined in: [src/auth.tsx:60](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L60)
 
 ***
 
@@ -30,7 +30,7 @@ Defined in: [src/auth.tsx:50](https://github.com/FirebaseExtended/reactfire/blob
 
 > **requiredClaims**: `object`
 
-Defined in: [src/auth.tsx:52](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L52)
+Defined in: [src/auth.tsx:62](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L62)
 
 #### Index Signature
 
@@ -42,4 +42,4 @@ Defined in: [src/auth.tsx:52](https://github.com/FirebaseExtended/reactfire/blob
 
 > **user**: `User`
 
-Defined in: [src/auth.tsx:49](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L49)
+Defined in: [src/auth.tsx:59](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L59)
diff --git a/docs/reference/interfaces/ClaimsValidator.md b/docs/reference/interfaces/ClaimsValidator.md
index e52f115e..feb558fd 100644
--- a/docs/reference/interfaces/ClaimsValidator.md
+++ b/docs/reference/interfaces/ClaimsValidator.md
@@ -6,11 +6,11 @@
 
 # Interface: ClaimsValidator()
 
-Defined in: [src/auth.tsx:81](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L81)
+Defined in: [src/auth.tsx:91](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L91)
 
 > **ClaimsValidator**(`claims`): `object`
 
-Defined in: [src/auth.tsx:82](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L82)
+Defined in: [src/auth.tsx:92](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L92)
 
 ## Parameters
 
diff --git a/docs/reference/interfaces/SignInCheckOptionsBasic.md b/docs/reference/interfaces/SignInCheckOptionsBasic.md
index b581c6c6..6c9f2d66 100644
--- a/docs/reference/interfaces/SignInCheckOptionsBasic.md
+++ b/docs/reference/interfaces/SignInCheckOptionsBasic.md
@@ -6,7 +6,7 @@
 
 # Interface: SignInCheckOptionsBasic
 
-Defined in: [src/auth.tsx:73](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L73)
+Defined in: [src/auth.tsx:83](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L83)
 
 ## Extends
 
@@ -23,7 +23,7 @@ Defined in: [src/auth.tsx:73](https://github.com/FirebaseExtended/reactfire/blob
 
 > `optional` **forceRefresh?**: `boolean`
 
-Defined in: [src/auth.tsx:74](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L74)
+Defined in: [src/auth.tsx:84](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L84)
 
 ***
 
diff --git a/docs/reference/interfaces/SignInCheckOptionsClaimsObject.md b/docs/reference/interfaces/SignInCheckOptionsClaimsObject.md
index 43a884ee..092cde82 100644
--- a/docs/reference/interfaces/SignInCheckOptionsClaimsObject.md
+++ b/docs/reference/interfaces/SignInCheckOptionsClaimsObject.md
@@ -6,7 +6,7 @@
 
 # Interface: SignInCheckOptionsClaimsObject
 
-Defined in: [src/auth.tsx:77](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L77)
+Defined in: [src/auth.tsx:87](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L87)
 
 ## Extends
 
@@ -18,7 +18,7 @@ Defined in: [src/auth.tsx:77](https://github.com/FirebaseExtended/reactfire/blob
 
 > `optional` **forceRefresh?**: `boolean`
 
-Defined in: [src/auth.tsx:74](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L74)
+Defined in: [src/auth.tsx:84](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L84)
 
 #### Inherited from
 
@@ -54,7 +54,7 @@ Defined in: [src/index.ts:26](https://github.com/FirebaseExtended/reactfire/blob
 
 > **requiredClaims**: `ParsedToken`
 
-Defined in: [src/auth.tsx:78](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L78)
+Defined in: [src/auth.tsx:88](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L88)
 
 ***
 
diff --git a/docs/reference/interfaces/SignInCheckOptionsClaimsValidator.md b/docs/reference/interfaces/SignInCheckOptionsClaimsValidator.md
index aeec944b..83517d7a 100644
--- a/docs/reference/interfaces/SignInCheckOptionsClaimsValidator.md
+++ b/docs/reference/interfaces/SignInCheckOptionsClaimsValidator.md
@@ -6,7 +6,7 @@
 
 # Interface: SignInCheckOptionsClaimsValidator
 
-Defined in: [src/auth.tsx:88](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L88)
+Defined in: [src/auth.tsx:98](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L98)
 
 ## Extends
 
@@ -18,7 +18,7 @@ Defined in: [src/auth.tsx:88](https://github.com/FirebaseExtended/reactfire/blob
 
 > `optional` **forceRefresh?**: `boolean`
 
-Defined in: [src/auth.tsx:74](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L74)
+Defined in: [src/auth.tsx:84](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L84)
 
 #### Inherited from
 
@@ -82,4 +82,4 @@ Defined in: [src/index.ts:31](https://github.com/FirebaseExtended/reactfire/blob
 
 > **validateCustomClaims**: [`ClaimsValidator`](ClaimsValidator.md)
 
-Defined in: [src/auth.tsx:89](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L89)
+Defined in: [src/auth.tsx:99](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L99)
diff --git a/docs/reference/type-aliases/SigninCheckResult.md b/docs/reference/type-aliases/SigninCheckResult.md
index 29f5bec9..bb80be74 100644
--- a/docs/reference/type-aliases/SigninCheckResult.md
+++ b/docs/reference/type-aliases/SigninCheckResult.md
@@ -8,4 +8,4 @@
 
 > **SigninCheckResult** = \{ `errors`: \{ \}; `hasRequiredClaims`: `false`; `signedIn`: `false`; `user`: `null`; \} \| \{ `errors`: [`ClaimCheckErrors`](../interfaces/ClaimCheckErrors.md); `hasRequiredClaims`: `boolean`; `signedIn`: `true`; `user`: `User`; \}
 
-Defined in: [src/auth.tsx:59](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L59)
+Defined in: [src/auth.tsx:69](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L69)
diff --git a/src/auth.tsx b/src/auth.tsx
index d535b894..7a1c4dfe 100644
--- a/src/auth.tsx
+++ b/src/auth.tsx
@@ -25,7 +25,17 @@ export function useUser<T = unknown>(options?: ReactFireOptions<T>): ObservableS
   const observableId = `auth:user:${auth.name}`;
   const observable$ = user(auth);
 
-  return useObservable(observableId, observable$, options);
+  const _options: ReactFireOptions<T> = { ...options };
+
+  // If a user is already signed in, seed initialData so consumers see the user
+  // synchronously on the first render without waiting for the async observable.
+  // We only do this when currentUser is truthy to avoid masking the uninitialized
+  // (null before auth has loaded from storage) case as "signed out".
+  if (auth.currentUser && !('initialData' in _options) && !('startWithValue' in _options)) {
+    _options.initialData = auth.currentUser as unknown as T;
+  }
+
+  return useObservable(observableId, observable$, _options);
 }
 
 export function useIdTokenResult(user: User, forceRefresh = false, options?: ReactFireOptions<IdTokenResult>): ObservableStatus<IdTokenResult> {
diff --git a/src/useObservable.ts b/src/useObservable.ts
index 08e8c748..fe05be5d 100644
--- a/src/useObservable.ts
+++ b/src/useObservable.ts
@@ -125,11 +125,24 @@ export function useObservable<T = unknown>(observableId: string, source: Observa
 
   const update = useSyncExternalStore(subscribe, getSnapshot);
 
-  // modify the value if initialData exists
+  // Return a new object with initialData overlaid rather than mutating the shared
+  // _immutableStatus reference, which is the same object across all components
+  // using the same observableId.
   if (!observable.hasValue && hasData) {
-    update.data = config?.initialData ?? config?.startWithValue;
-    update.status = 'success';
-    update.hasEmitted = true;
+    const initialDataValue = config?.initialData ?? config?.startWithValue;
+
+    // In suspense mode, throw errors so React Error Boundaries can catch them.
+    // In non-suspense mode, surface errors via status so consumers can handle them locally.
+    if (suspenseEnabled && update.error) {
+      throw update.error;
+    }
+
+    return {
+      ...update,
+      data: initialDataValue,
+      status: 'success',
+      hasEmitted: true,
+    } as ObservableStatus<T>;
   }
 
   // throw an error if there is an error
diff --git a/test/auth.test.tsx b/test/auth.test.tsx
index 61656426..c717754a 100644
--- a/test/auth.test.tsx
+++ b/test/auth.test.tsx
@@ -1,6 +1,8 @@
 import { cleanup, render, waitFor, renderHook, act } from '@testing-library/react';
 import '@testing-library/jest-dom/extend-expect';
 import * as React from 'react';
+import { NEVER } from 'rxjs';
+import { preloadObservable } from '../src/useObservable';
 import {
   FirebaseAppProvider,
   AuthCheck,
@@ -326,6 +328,39 @@ describe('Authentication', () => {
       expect(result.current.data).toEqual(getAuth(app).currentUser);
     });
 
+    it('synchronously returns the current user without waiting for the observable', async () => {
+      await act(async () => {
+        await signIn();
+      });
+
+      // Replace the auth:user observable with NEVER so it never emits.
+      // Without the fix (no initialData seeding), status is 'loading' on first render.
+      // With the fix (initialData = auth.currentUser), status is 'success' synchronously.
+      const cache = (globalThis as any)._reactFirePreloadedObservables as Map<string, any>;
+      const authUserKey = `auth:user:${getAuth(app).name}`;
+      cache?.delete(authUserKey);
+      preloadObservable(NEVER, authUserKey);
+
+      let capturedFirstRender: { user: any; status: string } | undefined;
+
+      const UserComponent = () => {
+        const { data: user, status } = useUser();
+        if (capturedFirstRender === undefined) {
+          capturedFirstRender = { user, status };
+        }
+        return <span data-testid="user-output">{String(status)}</span>;
+      };
+
+      try {
+        render(<UserComponent />, { wrapper: Provider });
+
+        expect(capturedFirstRender!.status).toBe('success');
+        expect(capturedFirstRender!.user).toEqual(getAuth(app).currentUser);
+      } finally {
+        cache?.delete(authUserKey);
+      }
+    });
+
     it('does not show a logged-out user after navigating away', async () => {
       await signIn();