佐々木勝彦

Inventor Goro Ibuki

林ゆたか

Hiroshi Jinkawa

Hiroyuki Kawase

Rokuro 'Roku-chan' Ibuki

富田浩太郎

Lead Seatopian Agent

Robert Dunham

Emperor Antonio of Seatopia

薩摩剣八郎

Gigan (as Kengo Nakayama)

納谷悟朗

Emperor Atonio of Seatopia (voice)

中島春雄

Godzilla (archive footage) (uncredited)