On screen
Cast
22 credited performers
Katsuhiko Sasaki
Inventor Goro Ibuki
Yutaka Hayashi
Hiroshi Jinkawa
Hiroyuki Kawase
Rokuro 'Roku-chan' Ibuki
Artwork unavailable
Kanta Mori
Japan Special Defense Forces Chief
Kotaro Tomita
Lead Seatopian Agent
Artwork unavailable
Ulf Otsuki
Seatopian Agent
Artwork unavailable
Sakyo Mikami
Truck Driver's Assistant
Artwork unavailable
Fumiyo Ikeda
Man from Unit 1
Robert Dunham
Emperor Antonio of Seatopia
Artwork unavailable
Gentaro Nakajima
Truck Driver
Artwork unavailable
Ralph Jesser
Antonio's Aide (Radio Operator in White)
Artwork unavailable
Shinji Takagi
Godzilla
Artwork unavailable
Hideto Odachi
Megalon
Artwork unavailable
Tsugutoshi Komada
Jet Jaguar
Artwork unavailable
Masachika Mori
Jet Jaguar
Kenpachirō Satsuma
Gigan
Gorō Naya
Emperor Atonio of Seatopia (voice)
Artwork unavailable
Eisuke Nakanishi
Narrator
Haruo Nakajima
Godzilla (archive footage) (uncredited)
Artwork unavailable
Kôetsu Ômiya
Anguirus
Artwork unavailable
Teruo Nigaki
Rodan
Artwork unavailable
Eisaburo Komatsu
Character not listed