Survivors of a sinking ship are rescued by Captain Nemo and his submarine crew. They are taken to an underwater city where they may spend the rest of their lives.
| Actor | Role |
|---|---|
 Robert RyanCaptain Nemo | Captain Nemo |
 Chuck ConnorsSenator Robert Fraser | Senator Robert Fraser |
 Nanette NewmanHelena Beckett | Helena Beckett |
 Luciana PaluzziMala | Mala |
 John TurnerJoab | Joab |
 Bill FraserBarnaby Bath | Barnaby Bath |
 Kenneth ConnorSwallow Bath | Swallow Bath |
 Allan CuthbertsonLomax | Lomax |
| CChristopher HartstonePhillip Beckett | Phillip Beckett |
| IIan RamseyAdam | Adam |
| JJohn MooreSkipper | Skipper |
| AAnthony BaileySailor | Sailor |
| AAlan BarrySailor | Sailor |
| VVincent HardingMate Navigator | Mate Navigator |