diff --git a/.changeset/green-peas-sit.md b/.changeset/green-peas-sit.md
new file mode 100644
index 000000000..b1f9b3975
--- /dev/null
+++ b/.changeset/green-peas-sit.md
@@ -0,0 +1,5 @@
+---
+'@web/rollup-plugin-polyfills-loader': patch
+---
+
+dont path.join on external urls, it breaks them
diff --git a/packages/rollup-plugin-polyfills-loader/src/rollupPluginPolyfillsLoader.ts b/packages/rollup-plugin-polyfills-loader/src/rollupPluginPolyfillsLoader.ts
index 5478f363f..7fe208599 100644
--- a/packages/rollup-plugin-polyfills-loader/src/rollupPluginPolyfillsLoader.ts
+++ b/packages/rollup-plugin-polyfills-loader/src/rollupPluginPolyfillsLoader.ts
@@ -88,7 +88,9 @@ export function polyfillsLoader(pluginOptions: RollupPluginPolyfillsLoaderConfig
           // js files (incl. chunks) will always be in the root directory
           const pathToRoot = path.posix.dirname(importPath);
           for (const chunkPath of entrypoint.chunk.imports) {
-            const relativeChunkPath = normalize(path.posix.join(pathToRoot, chunkPath));
+            const relativeChunkPath = normalize(
+              chunkPath.startsWith('http') ? chunkPath : path.posix.join(pathToRoot, chunkPath),
+            );
             preloaded.push(relativeChunkPath);
           }
         }