diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 048a323..ad1f93c 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -2,6 +2,11 @@ name: Test
 on:
   push:
   workflow_dispatch:
+    inputs:
+      run_ios:
+        description: Run the iOS simulator test
+        type: boolean
+        default: false
 
 jobs:
   testBrowser:
@@ -120,7 +125,7 @@ jobs:
       - name: Run tests
         run: npm run test:happy-dom
 
-  # Every environment gates now. Where a runtime deviates from the others, the deviation is pinned
+  # Where a runtime deviates from the others, the deviation is pinned
   # in `test/client.test.ts` with `test.fails` rather than excluded from CI, so that the suite goes
   # red again once the runtime is fixed and the workaround can come out. See CONTRIBUTING.md.
   testWorkerd:
@@ -138,6 +143,7 @@ jobs:
         run: npm run test:workerd
 
   testIos:
+    if: github.event_name == 'workflow_dispatch' && inputs.run_ios
     name: 'Test: iOS Simulator'
     timeout-minutes: 20
     runs-on: macos-latest
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 447aae6..f9957f8 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -38,6 +38,8 @@ The browser tests need Playwright's browsers installed once, with `npx playwrigh
 
 `test:ios` is out of `test:all` because it only runs on macOS with Xcode's iOS platform installed, but do reach for it whenever a report names an iPhone or iPad: Playwright's `webkit` is a desktop build with a different networking stack, so it is not evidence about iOS. It picks an iPhone on the newest installed iOS runtime, preferring one that is already booted; set `IOS_SIMULATOR_DEVICE` to pin a device by name, eg `IOS_SIMULATOR_DEVICE='iPad (A16)' npm run test:ios`. If nothing is installed, `xcodebuild -downloadPlatform iOS` fetches a runtime. The simulator is left booted afterwards, since booting one costs most of a minute.
 
+To run the iOS test in CI, open the **Test** workflow in GitHub Actions, choose **Run workflow**, and check **Run the iOS simulator test**.
+
 The provider (`test/helpers/iosSimulator.ts`) drives the simulator with `simctl` alone - Safari there is opened with `simctl openurl` and reports back over the websocket Vitest already opens, so no WebDriver or Appium stack is involved. That also means nothing in the suite can drive the page: keep the tests free of Vitest's browser locators and `userEvent`, which this provider does not implement.
 
 Use `test.fails` for runtime bugs when a future fix must turn the test red and prompt removal of the workaround: