diff --git a/packages/durable/src/testing/env-conformance.ts b/packages/durable/src/testing/env-conformance.ts
index 1fc2b23f6..0b98ce42c 100644
--- a/packages/durable/src/testing/env-conformance.ts
+++ b/packages/durable/src/testing/env-conformance.ts
@@ -99,10 +99,13 @@ export function createEnvConformance(options: EnvConformanceOptions): readonly E
 	const assert = options.assertions;
 	const shell = options.shell ?? ["sh", "-c"];
 	const symlinks = options.symlinks ?? true;
-	const createCase = (name: string, test: EnvTest): EnvConformanceCase => ({
+	const createCase = (name: string, test: EnvTest, timeoutMs?: number): EnvConformanceCase => ({
 		name,
+		...(timeoutMs === undefined ? {} : { timeoutMs }),
 		run: () => options.withEnv(test),
 	});
+	// Watch cases wait up to three seconds per step, longer than test runners allow by default.
+	const watchCase = (name: string, test: EnvTest): EnvConformanceCase => createCase(name, test, 30_000);
 	const execCollect = async (env: ExecutionEnv, command: string | readonly string[], cwd?: string) => {
 		const output: Record<ShellOutputInfo["stream"], string> = { stdout: "", stderr: "" };
 		const result = await env.exec(
@@ -253,7 +256,7 @@ export function createEnvConformance(options: EnvConformanceOptions): readonly E
 			}
 		}),
 
-		createCase("watch reports a missing file's creation, changes, replacement and removal", async (env) => {
+		watchCase("watch reports a missing file's creation, changes, replacement and removal", async (env) => {
 			await watching(env, [{ path: "AGENTS.md" }], async ({ expectChange }) => {
 				await expectChange("AGENTS.md", async () => {
 					getOrThrow(await env.writeFile("AGENTS.md", "one", context));
@@ -275,7 +278,7 @@ export function createEnvConformance(options: EnvConformanceOptions): readonly E
 			});
 		}),
 
-		createCase("watch reports a missing target whose ancestors are created", async (env) => {
+		watchCase("watch reports a missing target whose ancestors are created", async (env) => {
 			await watching(env, [{ path: "a/b/c/AGENTS.md" }], async ({ expectChange }) => {
 				await expectChange("a/b/c/AGENTS.md", async () => {
 					getOrThrow(await env.writeFile("a/b/c/AGENTS.md", "x", context));
@@ -283,7 +286,7 @@ export function createEnvConformance(options: EnvConformanceOptions): readonly E
 			});
 		}),
 
-		createCase("watch follows directories created together with their contents", async (env) => {
+		watchCase("watch follows directories created together with their contents", async (env) => {
 			getOrThrow(await env.createDir("skills", undefined, context));
 			await watching(env, [{ path: "skills", recursive: true }], async ({ expectChange }) => {
 				// Written before any watcher on the new directories can exist.
@@ -299,7 +302,7 @@ export function createEnvConformance(options: EnvConformanceOptions): readonly E
 			});
 		}),
 
-		createCase("watch keeps watching a path whose parent is renamed and recreated", async (env) => {
+		watchCase("watch keeps watching a path whose parent is renamed and recreated", async (env) => {
 			getOrThrow(await env.writeFile("proj/.pi/skills/x.md", "x", context));
 			await watching(env, [{ path: "proj/.pi/skills", recursive: true }], async ({ expectChange }) => {
 				await expectChange("proj/.pi/skills", async () => {
@@ -314,7 +317,7 @@ export function createEnvConformance(options: EnvConformanceOptions): readonly E
 			});
 		}),
 
-		createCase("watch skips excluded entries and reports a rename out of them", async (env) => {
+		watchCase("watch skips excluded entries and reports a rename out of them", async (env) => {
 			getOrThrow(await env.createDir("skills", undefined, context));
 			const targets: WatchTarget[] = [
 				{ path: "skills", recursive: true, exclude: { hidden: true, names: ["node_modules"] } },
@@ -338,7 +341,7 @@ export function createEnvConformance(options: EnvConformanceOptions): readonly E
 			});
 		}),
 
-		createCase("watch stops reporting once closed", async (env) => {
+		watchCase("watch stops reporting once closed", async (env) => {
 			const changes: WatchChange[] = [];
 			const watcher = getOrThrow(await env.watch([{ path: "file.txt" }], (change) => changes.push(change), context));
 			assert.ok(watcher.mode === "native" || watcher.mode === "polling", "watcher reports its mode");
diff --git a/packages/durable/src/testing/runner.ts b/packages/durable/src/testing/runner.ts
index 04bcd2a0c..c7d82d83f 100644
--- a/packages/durable/src/testing/runner.ts
+++ b/packages/durable/src/testing/runner.ts
@@ -6,7 +6,7 @@ import type { EnvConformanceOptions, EnvConformanceProvider, StorageConformanceP
 export interface StorageConformanceRunner {
 	readonly describe: (name: string, suite: () => void) => unknown;
 	readonly expect: ExpectLike;
-	readonly it: (name: string, test: () => Promise<void>) => unknown;
+	readonly it: (name: string, test: () => Promise<void>, timeoutMs?: number) => unknown;
 }
 
 /** Registers the runner-independent cases with a Vitest/Jest-compatible test runner. */
@@ -33,6 +33,6 @@ export function registerEnvConformance(
 ): void {
 	const cases = createEnvConformance({ ...options, assertions: createExpectAssertions(runner.expect), withEnv });
 	runner.describe(name, () => {
-		for (const testCase of cases) runner.it(testCase.name, testCase.run);
+		for (const testCase of cases) runner.it(testCase.name, testCase.run, testCase.timeoutMs);
 	});
 }
diff --git a/packages/durable/src/testing/types.ts b/packages/durable/src/testing/types.ts
index adfcc33c9..1b7ec09a5 100644
--- a/packages/durable/src/testing/types.ts
+++ b/packages/durable/src/testing/types.ts
@@ -38,5 +38,7 @@ export interface EnvConformanceOptions {
 
 export interface EnvConformanceCase {
 	readonly name: string;
+	/** Cases that wait for an environment's watch latency need longer than a test runner's default timeout. */
+	readonly timeoutMs?: number;
 	run(): Promise<void>;
 }