diff --git a/packages/start/src/server/handler.ts b/packages/start/src/server/handler.ts
index 9b1c9f218..f08f1f41c 100644
--- a/packages/start/src/server/handler.ts
+++ b/packages/start/src/server/handler.ts
@@ -114,12 +114,15 @@ export function createBaseHandler(
 
       if (mode === "async") return await stream;
 
-      delete (stream as any).then;
-
       // using TransformStream in dev can cause solid-start-dev-server to crash
       // when stream is cancelled
       if (globalThis.USING_SOLID_START_DEV_SERVER) return stream;
 
+      // remove thenable so h3/Cloudflare Workers do not await the stream object;
+      // must happen after the dev-server branch so the stream remains awaitable
+      // when returned to solid-start-dev-server above
+      delete (stream as any).then;
+
       // returning stream directly breaks cloudflare workers
       const { writable, readable } = new TransformStream();
       stream.pipeTo(writable);