Inventor Goro Ibuki
Hiroshi Jinkawa
Rokuro 'Roku-chan' Ibuki
Japan Special Defense Forces Chief
Lead Seatopian Agent
Seatopian Agent
Truck Driver's Assistant
Man from Unit 1
Emperor Antonio of Seatopia
Truck Driver
Antonio's Aide (Radio Operator in White)
Godzilla
Megalon
Jet Jaguar
Gigan (as Kengo Nakayama)
Emperor Atonio of Seatopia (voice)
Narrator
Godzilla (archive footage) (uncredited)
