Jason, a fearless sailor and explorer, returns to his home land of Thessaly after a long voyage to claim his rightful throne. He learns, however, that he must first find the magical Golden Fleece. To do so, he must embark on an epic quest fraught with fantastic monsters and terrible perils.
| Actor | Role |
|---|---|
 Todd ArmstrongJason | Jason |
 Nancy KovackMedea | Medea |
 Gary RaymondAcastus | Acastus |
 Laurence NaismithArgos | Argos |
 Niall MacGinnisZeus | Zeus |
 Michael GwynnHermes | Hermes |
 Douglas WilmerPelias | Pelias |
 Jack GwillimAeëtes | Aeëtes |
 Honor BlackmanHera | Hera |
 John CairneyHylas | Hylas |
 Patrick TroughtonPhineas | Phineas |
 Andrew FauldsPhalerus | Phalerus |
 Nigel GreenHercules | Hercules |
 John CrawfordPolydeuces (uncredited) | Polydeuces (uncredited) |
 Ferdinando PoggiCastor of Sparta (uncredited) | Castor of Sparta (uncredited) |
 Ennio AntonelliDmitrius, Drummer on Argo (uncredited) | Dmitrius, Drummer on Argo (uncredited) |
| HHarold BradleyGuard in Palace (uncredited) | Guard in Palace (uncredited) |
| AAldo CristianiLynceus (uncredited) | Lynceus (uncredited) |
| EEva HaddonMedea (voice) (uncredited) | Medea (voice) (uncredited) |
| DDoug RobinsonEupaemus (uncredited) | Eupaemus (uncredited) |
| DDavina TaylorBriseis (uncredited) | Briseis (uncredited) |
 Tim TurnerJason (voice) (uncredited) | Jason (voice) (uncredited) |
| BBill GudgeonTriton (uncredited) | Triton (uncredited) |