Please try this: In Xcode go to your watch target Pick the Build Settings tab Find the "Architectures" section with the "Supported Platforms" entry. Ensure the value for all configurations (expand the key if necessary) is set to watchOS. (I am guessing it is set to iphoneOS for your non-debug configurations) I have a theory that without explicitly setting it to watchOS for all configurations Xcode is inheriting values that Flutter has configured elsewhere in the project and it's incorrectly using the iPhone values.