 Michael KeithEric Carter | Eric Carter |
 Harry HolcombeDr. Arnold Johnson | Dr. Arnold Johnson |
 James YagiYutaka Omura | Yutaka Omura |
 Tadao TakashimaOsamu Sakurai | Osamu Sakurai |
 Kenji SaharaKazuo Fujita (as Keji Sahaka) | Kazuo Fujita (as Keji Sahaka) |
 Ichirō ArishimaMr. Tako (as Ichiro Arishima) | Mr. Tako (as Ichiro Arishima) |
 George TakeiOsamu Sakurai (voice) (uncredited) | Osamu Sakurai (voice) (uncredited) |
 Les TremayneMr. Tako / Dr. Shigesawa / Dr. Akira Makino / General Masami Shinzo / Commander Roberts / Narrator (voice) (uncredited) | Mr. Tako / Dr. Shigesawa / Dr. Akira Makino / General Masami Shinzo / Commander Roberts / Narrator (voice) (uncredited) |
 Byron MorrowNewscaster (uncredited) | Newscaster (uncredited) |
 Mie HamaFumiko Sakurai (uncredited) | Fumiko Sakurai (uncredited) |
 Akiko WakabayashiTamiye (uncredited) | Tamiye (uncredited) |
 Akemi NegishiChikiro's Mother (Dancing Girl) (uncredited) | Chikiro's Mother (Dancing Girl) (uncredited) |
 Akihiko HirataDr. Kenji Shigezawa (uncredited) | Dr. Kenji Shigezawa (uncredited) |
 Yū FujikiKinzaburo Furue (uncredited) | Kinzaburo Furue (uncredited) |
 Jun TazakiGeneral Masami Shinzo (uncredited) | General Masami Shinzo (uncredited) |
 Yoshio KosugiChief of Faro Island (uncredited) | Chief of Faro Island (uncredited) |
 Ikio SawamuraWitch Doctor (uncredited) | Witch Doctor (uncredited) |
 Kenzō TabuDreary Newscaster (uncredited) | Dreary Newscaster (uncredited) |
 Tatsuo MatsumuraDr. Akira Makino (uncredited) | Dr. Akira Makino (uncredited) |
 Victor MillanRodrigo Infanta (uncredited) | Rodrigo Infanta (uncredited) |
| DDouglas FeinCommander Roberts (uncredited) | Commander Roberts (uncredited) |
 Shōichi HiroseKing Kong (uncredited) | King Kong (uncredited) |
 Haruo NakajimaGodzilla (uncredited) | Godzilla (uncredited) |
 Katsumi TezukaGodzilla (iceberg scene) (uncredited) | Godzilla (iceberg scene) (uncredited) |
| PPaul MasonMisc. Characters (voice) (uncredited) | Misc. Characters (voice) (uncredited) |
| BBruce HowardMisc. Characters (voice) (uncredited) | Misc. Characters (voice) (uncredited) |
| CClifford HarringtonAl (uncredited) | Al (uncredited) |
