Alternative Wii game disc image format designed by Wii homebrew developers; contains an image of a Wii game that can be loaded onto a WBFS partition; used to store Wii games on Secure Digital (SD) or USB external devices that are formatted with the WBFS format.

After WBFS files have been stored on an external device, they can be run on the Wii using USB Loader, an application that loads WBFS disc images. However, this process is unofficial and is not supported by the manufacturer. WBFS files may be much smaller in size than a Wii game since they do not store the padding that is present in Wii disc images. NOTE: Wiithon can open WBFS files, as well as convert them to .ISO files.