diff --git a/packages/next/src/server/web/sandbox/timer-resource-lifecycle.test.ts b/packages/next/src/server/web/sandbox/timer-resource-lifecycle.test.ts
new file mode 100644
index 0000000000..1557cc681e
--- /dev/null
+++ b/packages/next/src/server/web/sandbox/timer-resource-lifecycle.test.ts
@@ -0,0 +1,126 @@
+import { clearAllModuleContexts, getModuleContext } from './context'
+
+async function createSandbox() {
+  return getModuleContext({
+    moduleName: `timer-lifecycle-${Math.random()}`,
+    onError: () => {},
+    onWarning: () => {},
+    useCache: false,
+    distDir: '/tmp',
+    edgeFunctionEntry: {
+      assets: [],
+      wasm: [],
+      env: {},
+    },
+  })
+}
+
+describe('sandbox timer resource lifecycle', () => {
+  let edgeGlobal: any
+
+  beforeEach(async () => {
+    edgeGlobal = (await createSandbox()).runtime.context
+  })
+
+  afterEach(async () => {
+    await clearAllModuleContexts()
+    jest.restoreAllMocks()
+    jest.useRealTimers()
+  })
+
+  it('releases completed one-shot timers across repeated rounds', async () => {
+    const clearTimeoutSpy = jest.spyOn(global, 'clearTimeout')
+    const callbackArg = () => 'callback value'
+    const rounds = 4
+    const timersPerRound = 8
+
+    for (let round = 0; round < rounds; round++) {
+      await Promise.all(
+        Array.from(
+          { length: timersPerRound },
+          () =>
+            new Promise<void>((resolve, reject) => {
+              edgeGlobal.setTimeout(
+                function (this: unknown, label: string, arg: () => string) {
+                  try {
+                    expect(this).toBe(edgeGlobal)
+                    expect(label).toBe('round')
+                    expect(arg).toBe(callbackArg)
+                    expect(arg()).toBe('callback value')
+                    resolve()
+                  } catch (error) {
+                    reject(error)
+                  }
+                },
+                0,
+                'round',
+                callbackArg
+              )
+            })
+        )
+      )
+    }
+
+    // Each completed Node timer is cleared once by the sandbox workaround.
+    expect(clearTimeoutSpy).toHaveBeenCalledTimes(rounds * timersPerRound)
+
+    await clearAllModuleContexts()
+
+    // Tearing down the still-live sandbox must not revisit timers that have
+    // already completed naturally.
+    expect(clearTimeoutSpy).toHaveBeenCalledTimes(rounds * timersPerRound)
+  })
+
+  it('stops tracking a one-shot timer even when its callback throws', async () => {
+    jest.useFakeTimers()
+    const clearTimeoutSpy = jest.spyOn(global, 'clearTimeout')
+
+    edgeGlobal.setTimeout(() => {
+      throw new Error('timer callback failed')
+    }, 0)
+
+    expect(() => jest.runOnlyPendingTimers()).toThrow('timer callback failed')
+    expect(clearTimeoutSpy).toHaveBeenCalledTimes(1)
+
+    await clearAllModuleContexts()
+    expect(clearTimeoutSpy).toHaveBeenCalledTimes(1)
+  })
+
+  it('cancels an explicitly cleared one-shot timer', async () => {
+    const clearTimeoutSpy = jest.spyOn(global, 'clearTimeout')
+    const callback = jest.fn()
+    const id = edgeGlobal.setTimeout(callback, 30)
+
+    edgeGlobal.clearTimeout(id)
+
+    expect(clearTimeoutSpy).toHaveBeenCalledWith(id)
+    await new Promise((resolve) => setTimeout(resolve, 60))
+    expect(callback).not.toHaveBeenCalled()
+
+    const callsAfterClear = clearTimeoutSpy.mock.calls.length
+    await clearAllModuleContexts()
+    expect(clearTimeoutSpy).toHaveBeenCalledTimes(callsAfterClear)
+  })
+
+  it('keeps repeating intervals tracked until sandbox teardown', async () => {
+    const clearIntervalSpy = jest.spyOn(global, 'clearInterval')
+    let ticks = 0
+    let resolveThirdTick: () => void
+    const thirdTick = new Promise<void>((resolve) => {
+      resolveThirdTick = resolve
+    })
+
+    const id = edgeGlobal.setInterval(() => {
+      ticks++
+      if (ticks === 3) resolveThirdTick()
+    }, 5)
+
+    await thirdTick
+    expect(ticks).toBeGreaterThanOrEqual(3)
+    expect(clearIntervalSpy).not.toHaveBeenCalled()
+
+    await clearAllModuleContexts()
+    expect(clearIntervalSpy).toHaveBeenCalledTimes(1)
+    expect(clearIntervalSpy).toHaveBeenCalledWith(id)
+  })
+})