This article explains what a GBA file is and how to open or convert it on your computer.
A file with the extension .GBA is a Game Boy Advance ROM file. It is an exact copy of a GBA video game.
If you have a GBA file on your computer, it means that the game has been copied from the read-only memory (ROM) chip on the console. You can use it on your computer or mobile device with an emulator, just as if you were playing it on the Game Boy Advance.
Some Game Boy Advance ROM files may have other file extensions, such as GB or AGB, but these should still function the same as GBA files.