diff --git a/common/api-review/auth.api.md b/common/api-review/auth.api.md
index aed0fb619da..27203e95f3a 100644
--- a/common/api-review/auth.api.md
+++ b/common/api-review/auth.api.md
@@ -95,6 +95,7 @@ export interface Auth {
     setPersistence(persistence: Persistence): Promise<void>;
     readonly settings: AuthSettings;
     signOut(): Promise<void>;
+    readonly tenantConfig?: TenantConfig;
     tenantId: string | null;
     updateCurrentUser(user: User | null): Promise<void>;
     useDeviceLanguage(): void;
diff --git a/docs-devsite/auth.auth.md b/docs-devsite/auth.auth.md
index cbbc7a9ceb0..1f96bd23881 100644
--- a/docs-devsite/auth.auth.md
+++ b/docs-devsite/auth.auth.md
@@ -31,6 +31,7 @@ export interface Auth
 |  [languageCode](./auth.auth.md#authlanguagecode) | string \| null | The [Auth](./auth.auth.md#auth_interface) instance's language code. |
 |  [name](./auth.auth.md#authname) | string | The name of the app associated with the <code>Auth</code> service instance. |
 |  [settings](./auth.auth.md#authsettings) | [AuthSettings](./auth.authsettings.md#authsettings_interface) | The [Auth](./auth.auth.md#auth_interface) instance's settings. |
+|  [tenantConfig](./auth.auth.md#authtenantconfig) | [TenantConfig](./auth.tenantconfig.md#tenantconfig_interface) | The [TenantConfig](./auth.tenantconfig.md#tenantconfig_interface) used to initialize a Regional Auth. This is only present if regional auth is initialized and  backend endpoint is used. |
 |  [tenantId](./auth.auth.md#authtenantid) | string \| null | The [Auth](./auth.auth.md#auth_interface) instance's tenant ID. |
 
 ## Methods
@@ -120,6 +121,16 @@ This is used to edit/read configuration related options such as app verification
 readonly settings: AuthSettings;
 ```
 
+## Auth.tenantConfig
+
+The [TenantConfig](./auth.tenantconfig.md#tenantconfig_interface) used to initialize a Regional Auth. This is only present if regional auth is initialized and  backend endpoint is used.
+
+<b>Signature:</b>
+
+```typescript
+readonly tenantConfig?: TenantConfig;
+```
+
 ## Auth.tenantId
 
 The [Auth](./auth.auth.md#auth_interface) instance's tenant ID.
diff --git a/packages/auth/src/api/index.test.ts b/packages/auth/src/api/index.test.ts
index 02042fce429..87f674807c0 100644
--- a/packages/auth/src/api/index.test.ts
+++ b/packages/auth/src/api/index.test.ts
@@ -25,7 +25,11 @@ import { FirebaseError, getUA } from '@firebase/util';
 import * as utils from '@firebase/util';
 
 import { mockEndpoint } from '../../test/helpers/api/helper';
-import { testAuth, TestAuth } from '../../test/helpers/mock_auth';
+import {
+  regionalTestAuth,
+  testAuth,
+  TestAuth
+} from '../../test/helpers/mock_auth';
 import * as mockFetch from '../../test/helpers/mock_fetch';
 import { AuthErrorCode } from '../core/errors';
 import { ConfigInternal } from '../model/auth';
@@ -34,6 +38,7 @@ import {
   _performApiRequest,
   DEFAULT_API_TIMEOUT_MS,
   Endpoint,
+  RegionalEndpoint,
   HttpHeader,
   HttpMethod,
   _addTidIfNecessary
@@ -55,9 +60,11 @@ describe('api/_performApiRequest', () => {
   };
 
   let auth: TestAuth;
+  let regionalAuth: TestAuth;
 
   beforeEach(async () => {
     auth = await testAuth();
+    regionalAuth = await regionalTestAuth();
   });
 
   afterEach(() => {
@@ -595,4 +602,34 @@ describe('api/_performApiRequest', () => {
         .and.not.have.property('tenantId');
     });
   });
+
+  context('throws Operation not allowed exception', () => {
+    it('when tenantConfig is not initialized and Regional Endpoint is used', async () => {
+      await expect(
+        _performApiRequest<typeof request, typeof serverResponse>(
+          auth,
+          HttpMethod.POST,
+          RegionalEndpoint.EXCHANGE_TOKEN,
+          request
+        )
+      ).to.be.rejectedWith(
+        FirebaseError,
+        'Firebase: Operations not allowed for the auth object initialized. (auth/operation-not-allowed).'
+      );
+    });
+
+    it('when tenantConfig is initialized and default Endpoint is used', async () => {
+      await expect(
+        _performApiRequest<typeof request, typeof serverResponse>(
+          regionalAuth,
+          HttpMethod.POST,
+          Endpoint.SIGN_UP,
+          request
+        )
+      ).to.be.rejectedWith(
+        FirebaseError,
+        'Firebase: Operations not allowed for the auth object initialized. (auth/operation-not-allowed).'
+      );
+    });
+  });
 });
diff --git a/packages/auth/src/api/index.ts b/packages/auth/src/api/index.ts
index af9b3c63bf1..a1480803449 100644
--- a/packages/auth/src/api/index.ts
+++ b/packages/auth/src/api/index.ts
@@ -26,6 +26,7 @@ import { AuthErrorCode, NamedErrorParams } from '../core/errors';
 import {
   _createError,
   _errorWithCustomMessage,
+  _operationNotSupportedForInitializedAuthInstance,
   _fail
 } from '../core/util/assert';
 import { Delay } from '../core/util/delay';
@@ -53,7 +54,7 @@ export const enum HttpHeader {
   X_FIREBASE_APP_CHECK = 'X-Firebase-AppCheck'
 }
 
-export const enum Endpoint {
+export enum Endpoint {
   CREATE_AUTH_URI = '/v1/accounts:createAuthUri',
   DELETE_ACCOUNT = '/v1/accounts:delete',
   RESET_PASSWORD = '/v1/accounts:resetPassword',
@@ -80,6 +81,10 @@ export const enum Endpoint {
   REVOKE_TOKEN = '/v2/accounts:revokeToken'
 }
 
+export enum RegionalEndpoint {
+  EXCHANGE_TOKEN = 'v2/${body.parent}:exchangeOidcToken'
+}
+
 const CookieAuthProxiedEndpoints: string[] = [
   Endpoint.SIGN_IN_WITH_CUSTOM_TOKEN,
   Endpoint.SIGN_IN_WITH_EMAIL_LINK,
@@ -139,10 +144,11 @@ export function _addTidIfNecessary<T extends { tenantId?: string }>(
 export async function _performApiRequest<T, V>(
   auth: Auth,
   method: HttpMethod,
-  path: Endpoint,
+  path: Endpoint | RegionalEndpoint,
   request?: T,
   customErrorMap: Partial<ServerErrorMap<ServerError>> = {}
 ): Promise<V> {
+  _assertValidEndpointForAuth(auth, path);
   return _performFetchWithErrorHandling(auth, customErrorMap, async () => {
     let body = {};
     let params = {};
@@ -322,6 +328,22 @@ export function _parseEnforcementState(
   }
 }
 
+function _assertValidEndpointForAuth(
+  auth: Auth,
+  path: Endpoint | RegionalEndpoint
+): void {
+  if (
+    !auth.tenantConfig &&
+    Object.values(RegionalEndpoint).includes(path as RegionalEndpoint)
+  ) {
+    throw _operationNotSupportedForInitializedAuthInstance(auth);
+  }
+
+  if (auth.tenantConfig && Object.values(Endpoint).includes(path as Endpoint)) {
+    throw _operationNotSupportedForInitializedAuthInstance(auth);
+  }
+}
+
 class NetworkTimeout<T> {
   // Node timers and browser timers are fundamentally incompatible, but we
   // don't care about the value here
diff --git a/packages/auth/src/core/auth/auth_impl.ts b/packages/auth/src/core/auth/auth_impl.ts
index 14c23ae28f3..d21cfdd0214 100644
--- a/packages/auth/src/core/auth/auth_impl.ts
+++ b/packages/auth/src/core/auth/auth_impl.ts
@@ -36,7 +36,8 @@ import {
   ErrorFn,
   NextFn,
   Unsubscribe,
-  PasswordValidationStatus
+  PasswordValidationStatus,
+  TenantConfig
 } from '../../model/public_types';
 import {
   createSubscribe,
@@ -126,6 +127,7 @@ export class AuthImpl implements AuthInternal, _FirebaseService {
     | undefined = undefined;
   _persistenceManagerAvailable: Promise<void>;
   readonly name: string;
+  readonly tenantConfig?: TenantConfig;
 
   // Tracks the last notified UID for state change listeners to prevent
   // repeated calls to the callbacks. Undefined means it's never been
@@ -140,7 +142,8 @@ export class AuthImpl implements AuthInternal, _FirebaseService {
     public readonly app: FirebaseApp,
     private readonly heartbeatServiceProvider: Provider<'heartbeat'>,
     private readonly appCheckServiceProvider: Provider<AppCheckInternalComponentName>,
-    public readonly config: ConfigInternal
+    public readonly config: ConfigInternal,
+    tenantConfig?: TenantConfig
   ) {
     this.name = app.name;
     this.clientVersion = config.sdkClientVersion;
@@ -149,6 +152,7 @@ export class AuthImpl implements AuthInternal, _FirebaseService {
     this._persistenceManagerAvailable = new Promise<void>(
       resolve => (this._resolvePersistenceManagerAvailable = resolve)
     );
+    this.tenantConfig = tenantConfig;
   }
 
   _initializeWithPersistence(
diff --git a/packages/auth/src/core/auth/register.ts b/packages/auth/src/core/auth/register.ts
index 52493945abc..efe1d63ab16 100644
--- a/packages/auth/src/core/auth/register.ts
+++ b/packages/auth/src/core/auth/register.ts
@@ -92,7 +92,8 @@ export function registerAuth(clientPlatform: ClientPlatform): void {
           app,
           heartbeatServiceProvider,
           appCheckServiceProvider,
-          config
+          config,
+          tenantConfig
         );
         _initializeAuthInstance(authInstance, deps);
 
diff --git a/packages/auth/src/core/util/assert.ts b/packages/auth/src/core/util/assert.ts
index 51dff0793e2..eb497fba8aa 100644
--- a/packages/auth/src/core/util/assert.ts
+++ b/packages/auth/src/core/util/assert.ts
@@ -112,6 +112,16 @@ export function _serverAppCurrentUserOperationNotSupportedError(
   );
 }
 
+export function _operationNotSupportedForInitializedAuthInstance(
+  auth: Auth
+): FirebaseError {
+  return _errorWithCustomMessage(
+    auth,
+    AuthErrorCode.OPERATION_NOT_ALLOWED,
+    'Operations not allowed for the auth object initialized.'
+  );
+}
+
 export function _assertInstanceOf(
   auth: Auth,
   object: object,
diff --git a/packages/auth/src/model/auth.ts b/packages/auth/src/model/auth.ts
index a88430fd5df..60faedef4e6 100644
--- a/packages/auth/src/model/auth.ts
+++ b/packages/auth/src/model/auth.ts
@@ -23,6 +23,7 @@ import {
   PasswordPolicy,
   PasswordValidationStatus,
   PopupRedirectResolver,
+  TenantConfig,
   User
 } from './public_types';
 import { ErrorFactory } from '@firebase/util';
@@ -100,6 +101,7 @@ export interface AuthInternal extends Auth {
 
   readonly name: AppName;
   readonly config: ConfigInternal;
+  readonly tenantConfig?: TenantConfig;
   languageCode: string | null;
   tenantId: string | null;
   readonly settings: AuthSettings;
diff --git a/packages/auth/src/model/public_types.ts b/packages/auth/src/model/public_types.ts
index ea997c7855f..bd6c9cc2b8c 100644
--- a/packages/auth/src/model/public_types.ts
+++ b/packages/auth/src/model/public_types.ts
@@ -183,6 +183,12 @@ export interface Auth {
   readonly name: string;
   /** The {@link Config} used to initialize this instance. */
   readonly config: Config;
+  /**
+   * The {@link TenantConfig} used to initialize a Regional Auth. This is only present
+   * if regional auth is initialized and {@link DefaultConfig.REGIONAL_API_HOST}
+   * backend endpoint is used.
+   */
+  readonly tenantConfig?: TenantConfig;
   /**
    * Changes the type of persistence on the `Auth` instance.
    *
diff --git a/packages/auth/test/helpers/mock_auth.ts b/packages/auth/test/helpers/mock_auth.ts
index e5e30fa1384..15c03dc42c1 100644
--- a/packages/auth/test/helpers/mock_auth.ts
+++ b/packages/auth/test/helpers/mock_auth.ts
@@ -116,6 +116,26 @@ export async function testAuth(
   return auth;
 }
 
+export async function regionalTestAuth(): Promise<TestAuth> {
+  const tenantConfig = { 'location': 'us', 'tenantId': 'tenant-1' };
+  const auth: TestAuth = new AuthImpl(
+    FAKE_APP,
+    FAKE_HEARTBEAT_CONTROLLER_PROVIDER,
+    FAKE_APP_CHECK_CONTROLLER_PROVIDER,
+    {
+      apiKey: TEST_KEY,
+      authDomain: TEST_AUTH_DOMAIN,
+      apiHost: TEST_HOST,
+      apiScheme: TEST_SCHEME,
+      tokenApiHost: TEST_TOKEN_HOST,
+      clientPlatform: ClientPlatform.BROWSER,
+      sdkClientVersion: 'testSDK/0.0.0'
+    },
+    tenantConfig
+  ) as TestAuth;
+  return auth;
+}
+
 export function testUser(
   auth: AuthInternal,
   uid: string,