diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 71da49cf..52926ea5 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -41,6 +41,13 @@ jobs:
 
       - run: pnpm install
 
+      # Download the time-skipping test server once, before the test loop. The
+      # binary is fetched lazily on first use and cached in the system temp dir;
+      # doing it here keeps the cold download off the critical path of any test's
+      # default 5s hook timeout (which flakes on slower runners).
+      - name: Pre-download time-skipping test server
+        run: pnpm prewarm-test-server
+
       - name: Build and test sample projects
         shell: bash
         run: |
diff --git a/package.json b/package.json
index 3753cfb2..8fc9e4fe 100644
--- a/package.json
+++ b/package.json
@@ -4,6 +4,7 @@
   "scripts": {
     "build": "pnpm run -r --filter './*' build",
     "test": "pnpm run -r --filter './*' test",
+    "prewarm-test-server": "node -e \"require('@temporalio/testing').TestWorkflowEnvironment.createTimeSkipping().then(e => e.teardown())\"",
     "format": "pnpm format:self ; pnpm run -r --filter './*' format",
     "format:self": "prettier --write .",
     "format:check": "pnpm format:check:self ; pnpm run -r --filter './*' format:check",
@@ -15,6 +16,7 @@
     "update-toc": "doctoc README.md"
   },
   "devDependencies": {
+    "@temporalio/testing": "^1.23.0",
     "doctoc": "^2.1.0",
     "glob": "^11.0.0",
     "husky": "^7.0.2",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 1397bf9a..7488939a 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -10,6 +10,9 @@ importers:
 
   .:
     devDependencies:
+      '@temporalio/testing':
+        specifier: ^1.23.0
+        version: 1.23.0(@swc/helpers@0.5.15)
       doctoc:
         specifier: ^2.1.0
         version: 2.2.1