Due to being created mainly as a research vehicle, the Bathysphere was never equipped with weapons, which has contributed to its various sinkings.
Rotor first used the Bathysphere to save Sonic from Jaws. Sonic used the air bubbles made by the submarine to not drown. Rotor later set out in his submarine to the Frozen North Sea, upon hearing his mother's voice on his radio in Knothole. Rotor also piloted it to Flicky Island, along with Sonic and Tails in the Sea Fox in order to find out what Dr. Robotnik was up to.