Lt. Commander Jiro Nomura

Akira Takarada

Commander Carl Nelson

Rhodes Reason

Madame Piranha

Mie Hama

Lieutenant Susan Watson

Linda Miller

Dr. Who

Hideyo Amamoto

Dr. Who

Eisei Amamoto

Susan

Linda G. Miller

Henchman

Yoshibumi Tajima

Henchman

Sachio Sakai

SDF General

Ryuji Kita

Henchman

Susumu Kurobe

Native

Ikio Sawamura

Henchman

Nadao Kirino

Henchman

Shōichi Hirose

Henchman

Kazuo Suzuki

Henchman

Tōru Ibuki

Naoya Kusakawa

King Kong

Haruo Nakajima

Mechani-Kong/Gorosaurus

Hiroshi Sekita

(voice)

Kei Taguchi

(voice)

Akiko Santo

Submariner (uncredited)

Osman Yusuf

Soldier (uncredited)

Tadashi Okabe

Soldier (uncredited)

Seishirō Kuno

General (uncredited)

Yasuhisa Tsutsumi

Reporter (uncredited)

Andrew Hughes