Traditionally, the most reliable way to obtain this file was through the bundle on Steam. Although the individual game has been delisted following the release of Sonic Origins , owners of the original collection can still locate it:
Open your and right-click SEGA Mega Drive & Genesis Classics . sonicknuckleswsonic3bin file work
Sonic 3 A.I.R. does not include the game data itself to avoid legal issues. You must provide the .bin file to initialize the game. Sonic 3 AIR - Port Details Traditionally, the most reliable way to obtain this