Glenn Ford
President Richardson
Robert Vaughn
Senator Barkley
Masao Kusakari
Doctor Shûzô Yoshizumi
Yumi Takigawa
Asami Noriko
Henry Silva
General Garland
Bo Svenson
Major Carter
Stephanie Faulkner
Sarah Baker
Cec Linder
Doctor Latour
Chuck Connors
Captain McCloud - HMS Nereid
George Kennedy
Admiral Conway
Olivia Hussey
Marit
Edward James Olmos
Captain Lopez
Isao Natsuyagi
Commander Nakanishi
Julie Khaner
Secretary - Palmer Station
George Touliatos
Col. Rankin
Sonny Chiba
Dr. Yamauchi
Tsunehiko Watase
Yasuo Tatsuno
Kensaku Morita
Ryûji Sanazawa
Toshiyuki Nagashima
Akimasa Matsuo
Nicholas Campbell
Radio Operator - Palmer Station
Chris Wiggins
Dr. Borodinov
Eve Crawford
Dr. Irma Ollich
John Bayliss
Major King
John Rutter
Sailor #1 - HMS Nereid
Alf Humphreys
Sailor #2 - HMS Nereid
Michael Tough
Young Sailor - HMS Nereid
Ken Ogata
Prof. Tsuchiya
William Binney
White House Aide Simmons
Stuart Gillard
Dr. Ed Meyer
Colin Fox
Spy Z
Ken Pogue
Dr. Krause
Alberta Watson
Litha (uncredited)
Mitsuko Oka
Tatsuno Yoshiko
Takashi Noguchi
Doctor's Assistant
Nenji Kobayashi
Doctor's Assistant #2
Haruki Kadokawa
Crew Member
Chū Takatsuki
Crew Member
Takeshige Hatanaka
Crew Member
Chikara Gonoue
Crew Member
Danielle Schneider
American Antarctic Crew Member