For New 3DS, check MicroSD Cards Compatible With New Nintendo 3DS. A computer with a built-in SD Card reader or an external SD Card drive.

Backing up the old SD card data If you're upgrading from an older 3DS (or just moving to a bigger SD card), you're going to need to back up the data from your old SD card.

You can format an SD card using Windows, Mac, and Android devices, and likely your digital camera too.

If you've got an SD or microSD card, knowing how to format it is essential. Here's how to do that on Android devices, computers, and cameras.

SD cards are enormously useful devices that hold more data every year. Reformatting an SD or microSD card can make sure all the data that was on it is gone.