Animal Crossing: New Horizons players with a Nintendo Switch Online subscription can now back their islands up to Nintendo’s cloud service.
To do this, press the Minus button on the game’s title screen (where you see the main logo and your villagers walking around). This will bring up Tom Nook, who will note that these settings deal with the more back-end things. From here, there’ll be an option that says “Island backup.” Select that choice.
Nook will warn that this is “only for use when your Nintendo Switch system has been lost or damaged,” and ask if you’re sure you want to enable the feature. Once you do, the game will backup to the cloud, even when you’re not playing. The last time your save has been backed up will now appear on the title screen in the bottom left corner.
In order to download the island backup, you have to contact Nintendo directly.