Nintendo Switch demo details
The official demo page lists the Nintendo Switch demo and publishes a 3 GB minimum capacity for it. Keep extra space for downloads and updates.
Transfer conditions
The demo and full version must use the same platform and account. Keep the demo save file. If the console asks you to update the full game, complete that update before trying to transfer.
If the option does not appear
Confirm the demo is installed on the account that owns the full game, then check the game’s own title-screen instructions. Do not delete the demo save while troubleshooting.