Big Kahuna Island was an island on Mobius and was home to West Robotropolis. It was used as a secret base by Snively and a group of other convicts after their escape from the Devil's Gulag. Sonic the Hedgehog and members of the Royal Secret Service traveled to Big Kahuna Island via a submarine to retrieve Nate Morgan, who had been captured by Snively and his goons. It also turned out that the underside of the island was the resting place of a giant squid Mutate that was brought out of dormancy when one of Robo-Robotnik's satellites orbiting overhead reactivated, broke through the surface, and caused even more damage to the already ruined structures. (StH: #68, #70)
- According to the original World Map, Big Kahuna Island was located near Devil's Gulag in the Great Mobocean (the Pacific). However, the new World Map depicts the two islands in seperate oceans; with Devil's Gulag being relocated to the Central Sea (the Gulf of Mexico).
- According to The Complete Sonic Comic Encyclopedia world map, the island is under the control of the Eggman Empire.