diff --git a/.changeset/tough-countries-kiss.md b/.changeset/tough-countries-kiss.md
new file mode 100644
index 000000000000..621d915e4ef2
--- /dev/null
+++ b/.changeset/tough-countries-kiss.md
@@ -0,0 +1,15 @@
+---
+"wrangler": patch
+---
+
+ci: use `npm ci` and do not cache workspace packages in node_modules
+
+Previously we were caching all the `node_modules` files in the CI jobs and then running `npm install`. While this resulted in slightly improved install times on Ubuntu, it breaks on Windows because the npm workspace setup adds symlinks into node_modules, which the Github cache action cannot cope with.
+
+This change removes the `node_modules` caches (saving some time by not needing to restore them) and replaces `npm install` with `npm ci`.
+
+The `npm ci` command is actually designed to be used in CI jobs as it only installs the exact versions specified in the `package-lock.json` file, guaranteeing that for any commit we always have exactly the same CI job run, deterministically.
+
+It turns out that, on Ubuntu, using `npm ci` makes very little difference to the installation time (~30 secs), especially if there is no `node_modules` there in the first place.
+
+Unfortunately, MacOS is slower (~1 min), and Windows even worse (~2 mins)! But it is worth this longer CI run to be sure we have things working on all OSes.
diff --git a/.github/workflows/pullrequests.yml b/.github/workflows/pullrequests.yml
index 4c681e781816..214410b22be7 100644
--- a/.github/workflows/pullrequests.yml
+++ b/.github/workflows/pullrequests.yml
@@ -21,14 +21,6 @@ jobs:
           node-version: 16.7
           cache: "npm"
 
-      - uses: actions/cache@v2
-        id: node-modules-cache
-        with:
-          path: |
-            node_modules
-            */*/node_modules
-          key: ${{ matrix.os }}-node-${{ hashFiles('**/package-lock.json') }}
-
       - uses: actions/cache@v2
         id: eslint-cache
         with:
@@ -38,7 +30,7 @@ jobs:
           key: ${{ matrix.os }}-eslint-tsbuildinfo-${{ hashFiles('**/*.ts','**/*.js', 'package.json', 'tsconfig.json') }}
 
       - name: Install NPM Dependencies
-        run: npm install
+        run: npm ci
 
       - name: Check for errors
         run: npm run check
@@ -61,16 +53,8 @@ jobs:
           node-version: 16.7
           cache: "npm"
 
-      - uses: actions/cache@v2
-        id: node-modules-cache
-        with:
-          path: |
-            node_modules
-            */*/node_modules
-          key: ${{ matrix.os }}-node-${{ hashFiles('**/package-lock.json') }}
-
       - name: Install NPM Dependencies
-        run: npm install
+        run: npm ci
 
       - name: Run build and test
         run: npm run build-and-test