Cocoa Island is a remote island in the south-western Mobian Ocean on which Tails has a workshop. He found it in 3235 when he was heading home from his adventure in Downunda during the First Robotnik War. When Sonic was thought to have perished in the Xorda attack on Mobius, Tails used it as his home away from home to help him cope through the "dark times". While Tails initially recorded the island as having two smaller sister islands when he first surveyed the area, a third island was found when he brought Bunnie "Rabbot" D'Coolette and Antoine D'Coolette there for an overdue honeymoon. (TMS: #3 , StH: #125 , SU: #17)
The third island turned out to be the well-disguised Battle Fortress of an organization known as the Battle Bird Armada, who observed the trio secretly for several hours before launching a landing party. In the ensuing confrontation, the island's jungle was set on fire, and the D'Coolettes were subdued while Tails was forced to hide from Speedy, the sixteenth Battlekukku. Tails then set about exploring the Armada's operations after retrieving the Sea Fox, only to engage several of their submersibles off the coast. (SU: #17, #18)
With a water-based entrance no longer an option, Tails, T-Pup, and the recently rescued Antoine went into the island's robust cave network to locate a tunnel below the seabed that lead to the Armada's base. The cavern tunnels further underground appeared to have been carved out by some ancient civilization that had long since left the island and may have been what gained Battlekukku XV's attention as the Armada was looking for clues to the secrets of their forbears, the ancient Babylonians. The island's ruins were apparently known to the Babylon Rogues as well, who were also looking for relics from Babylon that they believed only they had the right to take and may have been on Cocoa Island. Regardless, the Armada withdrew after their Fortress took substantial damage thanks to Tails, and the Rouges then went on an intercept course with the Armada, allowing Cocoa Island to return to its peaceful state. (SU: #19, #20)
- Cocoa Island is the setting for the Game Gear game Tails Adventure, of which its debut story arc is based. The island has also been known as Kokko Island in some media.