King Dedede's Submarine is one of many mechanical contraptions used by King Dedede in the anime Kirby: Right Back at Ya! and was only featured in the episode A Fish Called Kine before it was destroyed. Not long after Dedede made a "trade-off" with Kine providing him with a fish tank so he could be with Tiff, he and Escargoon went to work piloting their submarine as they went on to attack and wreck the Rainbow Coral Reef. But Kine found out and, aided by Kirby and his friends, came to stop them. However, Kine was quickly bested, and Team Kirby's own submarine was wrecked by a torpedo from Dedede's own (but thankfully Kine was able to put bubble shields around Tiff and Tuff). The pink hero was caught and given a pounding until Kine freed him, and Kirby used his Inhale and managed to suck in the submarine's propeller, thus becoming Tornado Kirby. Using his tornado, he was able to rip the king's submarine apart, after which both Dedede and Escargoon were chased by Joe the shark.
King Dedede's Submarine is cubic in appearance, except at its back. It is just like any other submarine, with a propeller at its back and a window on its front. It also has two mechanical clawed appendages, as well as hidden features like a boxing glove to bash opponents with, and even comes complete with torpedo launchers.
The submarine is actually an invention of Escargoon's, rather than an invention purchased from Nightmare Enterprises (like Dedede would later do with his Limosuine).