diff --git a/packages/nuxt/test/runtime/plugins/client.test.ts b/packages/nuxt/test/runtime/plugins/client.test.ts
new file mode 100644
index 000000000000..092a5ed4a20b
--- /dev/null
+++ b/packages/nuxt/test/runtime/plugins/client.test.ts
@@ -0,0 +1,255 @@
+import type { Client } from '@sentry/core';
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import clientPlugin from '../../../src/runtime/plugins/sentry.client';
+import * as utils from '../../../src/runtime/utils';
+
+const getClient = vi.hoisted(() => vi.fn<() => Client | undefined>());
+const browserTracingIntegration = vi.hoisted(() => vi.fn());
+const vueIntegration = vi.hoisted(() => vi.fn());
+const createVueRouteProvider = vi.hoisted(() => vi.fn());
+const getRouteProvider = vi.hoisted(() => vi.fn());
+const setRouteProvider = vi.hoisted(() => vi.fn());
+
+vi.mock(import('@sentry/core'), async importOriginal => {
+  const mod = await importOriginal();
+  return { ...mod, getClient, GLOBAL_OBJ: {} as never };
+});
+
+vi.mock(import('@sentry/vue'), async importOriginal => {
+  const mod = await importOriginal();
+  return {
+    ...mod,
+    browserTracingIntegration,
+    vueIntegration,
+    _INTERNAL_createVueRouteProvider: createVueRouteProvider,
+    getRouteProvider,
+    setRouteProvider,
+  };
+});
+
+vi.mock(import('nuxt/app'), () => ({
+  defineNuxtPlugin: vi.fn(plugin => plugin),
+  isNuxtError: vi.fn(() => false),
+}));
+
+type PluginSetup = (nuxtApp: {
+  $router?: unknown;
+  hook: ReturnType<typeof vi.fn>;
+}) => Promise<void>;
+
+type NuxtPluginShape = { setup: PluginSetup };
+
+function makeClient(overrides: Partial<Client> = {}): Client {
+  return {
+    addIntegration: vi.fn(),
+    getOptions: vi.fn(() => ({ attachProps: true })),
+    ...overrides,
+  } as unknown as Client;
+}
+
+function makeNuxtApp(router?: unknown): { $router?: unknown; hook: ReturnType<typeof vi.fn> } {
+  return router === undefined ? { hook: vi.fn() } : { $router: router, hook: vi.fn() };
+}
+
+describe('Sentry Nuxt client plugin', () => {
+  afterEach(() => {
+    vi.resetAllMocks();
+  });
+
+  describe('route provider setup', () => {
+    it('installs a Vue route provider when a Nuxt router is present and none is set', async () => {
+      const router = { beforeEach: vi.fn(), onError: vi.fn() };
+      const client = makeClient();
+      const provider = { resolveRoute: vi.fn(), resolveCurrentRoute: vi.fn() };
+      getClient.mockReturnValue(client);
+      getRouteProvider.mockReturnValue(undefined);
+      createVueRouteProvider.mockReturnValue(provider);
+
+      await (clientPlugin as NuxtPluginShape).setup(makeNuxtApp(router));
+
+      expect(createVueRouteProvider).toHaveBeenCalledTimes(1);
+      // The provider is a lazy router getter — confirm it resolves to our router.
+      const routerGetter = createVueRouteProvider.mock.calls[0]![0] as () => unknown;
+      expect(routerGetter()).toBe(router);
+      expect(setRouteProvider).toHaveBeenCalledWith(provider, client);
+    });
+
+    it('does not override a user-supplied route provider', async () => {
+      const client = makeClient();
+      getClient.mockReturnValue(client);
+      getRouteProvider.mockReturnValue({ resolveRoute: () => '/u', resolveCurrentRoute: () => '/u' });
+
+      await (clientPlugin as NuxtPluginShape).setup(makeNuxtApp({}));
+
+      expect(createVueRouteProvider).not.toHaveBeenCalled();
+      expect(setRouteProvider).not.toHaveBeenCalled();
+    });
+
+    it('skips route provider setup without an initialized client', async () => {
+      getClient.mockReturnValue(undefined);
+
+      await (clientPlugin as NuxtPluginShape).setup(makeNuxtApp({}));
+
+      expect(createVueRouteProvider).not.toHaveBeenCalled();
+      expect(setRouteProvider).not.toHaveBeenCalled();
+    });
+
+    it('skips route provider setup without a $router on the Nuxt app', async () => {
+      const client = makeClient();
+      getClient.mockReturnValue(client);
+      getRouteProvider.mockReturnValue(undefined);
+
+      await (clientPlugin as NuxtPluginShape).setup(makeNuxtApp());
+
+      expect(createVueRouteProvider).not.toHaveBeenCalled();
+      expect(setRouteProvider).not.toHaveBeenCalled();
+    });
+  });
+
+  describe('browser tracing integration', () => {
+    it('adds browserTracingIntegration with the Nuxt router and path-based labels', async () => {
+      const router = { beforeEach: vi.fn(), onError: vi.fn() };
+      const integration = { name: 'BrowserTracing' };
+      const client = makeClient();
+      getClient.mockReturnValue(client);
+      getRouteProvider.mockReturnValue(undefined);
+      browserTracingIntegration.mockReturnValue(integration);
+
+      await (clientPlugin as NuxtPluginShape).setup(makeNuxtApp(router));
+
+      expect(browserTracingIntegration).toHaveBeenCalledWith({ router, routeLabel: 'path' });
+      expect(client.addIntegration).toHaveBeenCalledWith(integration);
+    });
+
+    it('does not add browserTracingIntegration without an initialized client', async () => {
+      getClient.mockReturnValue(undefined);
+
+      await (clientPlugin as NuxtPluginShape).setup(makeNuxtApp({ beforeEach: vi.fn() }));
+
+      expect(browserTracingIntegration).not.toHaveBeenCalled();
+    });
+
+    it('does not add browserTracingIntegration when the Nuxt app has no router', async () => {
+      const client = makeClient();
+      getClient.mockReturnValue(client);
+      getRouteProvider.mockReturnValue(undefined);
+
+      await (clientPlugin as NuxtPluginShape).setup(makeNuxtApp());
+
+      expect(browserTracingIntegration).not.toHaveBeenCalled();
+    });
+  });
+
+  describe('app:created hook — Vue integration', () => {
+    it('adds the Nuxt-specific Vue integration with attachErrorHandler disabled', async () => {
+      const client = makeClient();
+      const integration = { name: 'NuxtVueIntegration' };
+      const vueApp = { Symbol: 'app' };
+      getClient.mockReturnValue(client);
+      getRouteProvider.mockReturnValue(undefined);
+      vueIntegration.mockReturnValue(integration);
+
+      const nuxtApp = makeNuxtApp();
+      await (clientPlugin as NuxtPluginShape).setup(nuxtApp);
+      const appCreatedCall = nuxtApp.hook.mock.calls.find(c => c[0] === 'app:created');
+      expect(appCreatedCall).toBeTruthy();
+      const appCreatedCb = appCreatedCall![1] as (app: unknown) => void;
+      appCreatedCb(vueApp);
+
+      expect(vueIntegration).toHaveBeenCalledTimes(1);
+      const vueCallArgs = vueIntegration.mock.calls[0]![0] as {
+        app: unknown;
+        attachErrorHandler: boolean;
+      };
+      expect(vueCallArgs.app).toBe(vueApp);
+      expect(vueCallArgs.attachErrorHandler).toBe(false);
+      expect(client.addIntegration).toHaveBeenCalledWith(integration);
+    });
+
+    it('does not add the Vue integration when the client is gone by the time the hook fires', async () => {
+      const client = makeClient();
+      getClient.mockReturnValueOnce(client);
+      getRouteProvider.mockReturnValue(undefined);
+
+      const nuxtApp = makeNuxtApp();
+      await (clientPlugin as NuxtPluginShape).setup(nuxtApp);
+
+      // Second getClient call (inside the hook) returns undefined — simulates teardown.
+      getClient.mockReturnValueOnce(undefined);
+      const appCreatedCb = nuxtApp.hook.mock.calls.find(c => c[0] === 'app:created')?.[1] as (app: unknown) => void;
+      appCreatedCb({});
+
+      expect(vueIntegration).not.toHaveBeenCalled();
+    });
+  });
+
+  describe('app:error hook — status-code filtering', () => {
+    it('skips reporting when a Nuxt error carries a 4xx status code', async () => {
+      const { isNuxtError } = await import('nuxt/app');
+      const reportSpy = vi.spyOn(utils, 'reportNuxtError').mockImplementation(() => {});
+      vi.mocked(isNuxtError).mockReturnValue(true);
+      getClient.mockReturnValue(makeClient());
+      getRouteProvider.mockReturnValue(undefined);
+
+      const nuxtApp = makeNuxtApp();
+      await (clientPlugin as NuxtPluginShape).setup(nuxtApp);
+      const errorCb = nuxtApp.hook.mock.calls.find(c => c[0] === 'app:error')?.[1] as (e: unknown) => void;
+      errorCb({ statusCode: 404 });
+
+      expect(reportSpy).not.toHaveBeenCalled();
+    });
+
+    it('reports a Nuxt error when the status code is 5xx', async () => {
+      const { isNuxtError } = await import('nuxt/app');
+      const reportSpy = vi.spyOn(utils, 'reportNuxtError').mockImplementation(() => {});
+      vi.mocked(isNuxtError).mockReturnValue(true);
+      getClient.mockReturnValue(makeClient());
+      getRouteProvider.mockReturnValue(undefined);
+
+      const nuxtApp = makeNuxtApp();
+      await (clientPlugin as NuxtPluginShape).setup(nuxtApp);
+      const errorCb = nuxtApp.hook.mock.calls.find(c => c[0] === 'app:error')?.[1] as (e: unknown) => void;
+      const err = { statusCode: 503, message: 'bad gateway' };
+      errorCb(err);
+
+      expect(reportSpy).toHaveBeenCalledWith({ error: err });
+    });
+
+    it('reports a non-Nuxt error regardless of status code shape', async () => {
+      const { isNuxtError } = await import('nuxt/app');
+      const reportSpy = vi.spyOn(utils, 'reportNuxtError').mockImplementation(() => {});
+      vi.mocked(isNuxtError).mockReturnValue(false);
+      getClient.mockReturnValue(makeClient());
+      getRouteProvider.mockReturnValue(undefined);
+
+      const nuxtApp = makeNuxtApp();
+      await (clientPlugin as NuxtPluginShape).setup(nuxtApp);
+      const errorCb = nuxtApp.hook.mock.calls.find(c => c[0] === 'app:error')?.[1] as (e: unknown) => void;
+      const err = new Error('boom');
+      errorCb(err);
+
+      expect(reportSpy).toHaveBeenCalledWith({ error: err });
+    });
+  });
+
+  describe('vue:error hook', () => {
+    it('forwards the error, component instance and info to reportNuxtError', async () => {
+      const reportSpy = vi.spyOn(utils, 'reportNuxtError').mockImplementation(() => {});
+      getClient.mockReturnValue(makeClient());
+      getRouteProvider.mockReturnValue(undefined);
+
+      const nuxtApp = makeNuxtApp();
+      await (clientPlugin as NuxtPluginShape).setup(nuxtApp);
+      const vueErrorCb = nuxtApp.hook.mock.calls.find(c => c[0] === 'vue:error')?.[1] as (
+        e: unknown,
+        instance: unknown,
+        info: string,
+      ) => void;
+      const err = new Error('vue boom');
+      const instance = { $props: { foo: 1 } };
+      vueErrorCb(err, instance, 'render');
+
+      expect(reportSpy).toHaveBeenCalledWith({ error: err, instance, info: 'render' });
+    });
+  });
+});