Kenji Sahara

Shigeru Kawamura (as Kenji Sawara)

Yumi Shirakawa

Kiyo

Akihiko Hirata

Dr. Kyuichiro Kashiwagi

Akio Kobori

Police Chief Nishimura

Minosuke Yamada

Mining Director Osaki

Yoshifumi Tajima

Izeki

Keye Luke

Shigeru Kawamura / Sunagawa / Police Officer Toji (voice) (uncredited)

George Takei

Dr. Kyuichiro Kashiwagi / Izeki / Male Honeymooner (voice) (uncredited)

Paul Frees

Police Chief Nishimura / Suda / Dr. Tanaka / Air Force Officer / Air Force Pilot Kitahara (voice) (uncredited)

Marvin Miller

Air Self-Defense Force Commander / Air Force Pilot / Newsreader (voice) (uncredited)

James Yagi

Osaki / Professor Minami / Hotel Manager / Farmer (voice) (uncredited)

Art Gilmore

Narrator (voice) (uncredited)

Fay Wray

Screaming Woman in Crowd (voice) (archival) (uncredited)

Murray Spivack

Screaming Police Officers (voice) (archival) (uncredited)

Haruo Nakajima

Rodan / Meganulon (uncredited)

Katsumi Tezuka

Hotel Manager / Rodan / Meganulon (uncredited)

Shōichi Hirose

Fighter Pilot / Meganulon (uncredited)