Ocean moons are often classed as S3-planets, with a breathable atmosphere to humans, and were therefore often explored by the Space Corps. However they are defined by having little to no dry land, and are mostly if not entirely covered in ocean, and often are fairly inhospitable.
- Red Dwarf once passed by an ocean moon, and Lister, Cat, Kryten and Holly decided to go on a "fishing holiday" even though a scouter had determined that there was no fish. The truth was, they just all wanted some time away from Rimmer, although they accidentally awoke Rimmer on the way out. In orbit around the ocean moon, their shuttle Starbug crashed into the dimension-jumping ship Wildfire and nose-dived down onto some rocks. However, the pilot of the Wildfire was Ace Rimmer - a courageous and capable alternate version of their own Rimmer, who came aboard and helped them fix the 'bugs engines, much to the resentment of their own Rimmer. ("Dimension Jump", Series IV)
- The Dwarfers explored the underwater wreck of the SSS Esperanto at the bottom of an ocean moon, which had been a terraforming vessel and had seeded the ocean moon with life. However, the Dwarfers succumbed to intense group hallucinations brought on by the ink of an attacking Despair Squid. This caused them to believe they were merely playing a game on a Fascist Earth. However, Holly was able to destroy the Squid with limpet mines, and wake the gang up before they committed group suicide. ("Back to Reality", Series V)
- After having lost Red Dwarf for two series since the SSS Esperanto incident, the Dwarfers eventually take Starbug back to the same ocean moon where they last parked it. Nearby to the ocean moon they discover the truth of what happened to Red Dwarf - Kryten's nanobot's had turned Red Dwarf into a planetoid. They then convince the nanobots to turn the planetoid back into their mothership, which they do, also resurrecting the rest of the old crew (who had died in the radiation leak three million years previously) in the process. The nanobots flee, and Captain Hollister promptly has the regular characters thrown in the ship's brig for stealing a Starbug. (Prelude to Nanarchy, "Nanarchy", Back in the Red)
- Whilst serving as Canaries, the Dwarfers are ordered to go down into another ocean moon to investigate the underwater wreck of the SS Silverberg. They went out in the Canary shuttle and down in a Diving Bell. Here they discover Cassandra, an AI who can tell the future, and wants Lister to suffer for something he has yet to do. ("Cassandra", Series VIII)
- Another Despair Squid from the SSS Esperanto moon had stowed away in the Red Dwarf Water Tank, kept in secret by the Cat for a later fishy snack. However, this squid would also later cause group hallucinations for the Dwarfers, in which they believed that they had returned home to Earth. After realising that it was a "hope squid" instead of a despair, they dropped off the squid at the nearest ocean moon to create some happy sea life. (Back to Earth)
- Many years later, the Dwarfers encounter an ocean moon with yet another underwater wreck, the SS Samsara. After encountering two crew in an orbiting escape pod - albeit who do not survive long after coming out of stasis - the Dwarfers believe that they may find more humans in stasis. They go down to the underwater wreck to investigate, only to discover an nightmare as a haywire Karma Drive causes chaos and prevents them from leaving. ("Samsara", Series XI)