diff --git a/src/utils/example-webcontainer-start.ts b/src/utils/example-webcontainer-start.ts
index f2edf5987..efb705388 100644
--- a/src/utils/example-webcontainer-start.ts
+++ b/src/utils/example-webcontainer-start.ts
@@ -129,7 +129,8 @@ export function getWebContainerStartCommand(runtime: ExampleRuntime) {
   }
 
   const args = [...runtime.start.args]
-  if (!args.includes('--')) args.push('--')
+  // npm needs `--` to forward args. pnpm would pass the `--` itself on to Vite, which ignores what follows.
+  if (runtime.start.command === 'npm' && !args.includes('--')) args.push('--')
   args.push('--config', tanStackStartViteConfigPath.slice(1))
 
   return { command: runtime.start.command, args }
diff --git a/tests/example-webcontainer-start.test.ts b/tests/example-webcontainer-start.test.ts
index 0a683da7f..f53c0bf53 100644
--- a/tests/example-webcontainer-start.test.ts
+++ b/tests/example-webcontainer-start.test.ts
@@ -99,8 +99,18 @@ describe('TanStack Start WebContainer compatibility', () => {
   test('starts Vite with the hidden config only for the Start profile', () => {
     assert.deepEqual(getWebContainerStartCommand(startRuntime), {
       command: 'pnpm',
-      args: ['run', 'dev', '--', '--config', '.tanstack/vite.config.mjs'],
+      args: ['run', 'dev', '--config', '.tanstack/vite.config.mjs'],
     })
+    assert.deepEqual(
+      getWebContainerStartCommand({
+        ...startRuntime,
+        start: { command: 'npm', args: ['run', 'dev'] },
+      }),
+      {
+        command: 'npm',
+        args: ['run', 'dev', '--', '--config', '.tanstack/vite.config.mjs'],
+      },
+    )
 
     assert.deepEqual(
       getWebContainerStartCommand({