diff --git a/playwright/_impl/_network.py b/playwright/_impl/_network.py
index 3e9685e6e..558a9f736 100644
--- a/playwright/_impl/_network.py
+++ b/playwright/_impl/_network.py
@@ -209,10 +209,10 @@ async def sizes(self) -> RequestSizes:
     def post_data(self) -> Optional[str]:
         data = self._fallback_overrides.post_data_buffer
         if data:
-            return data.decode()
+            return data.decode(errors="replace")
         base64_post_data = self._initializer.get("postData")
         if base64_post_data is not None:
-            return base64.b64decode(base64_post_data).decode()
+            return base64.b64decode(base64_post_data).decode(errors="replace")
         return None
 
     @property