Glenn Ford as President Richardson

Robert Vaughn as Senator Barkley

Masao Kusakari as Doctor Shûzô Yoshizumi

Yumi Takigawa as Asami Noriko

Henry Silva as General Garland

Bo Svenson as Major Carter

Stephanie Faulkner as Sarah Baker

Stuart Gillard as Doctor Ed Meyer

Cec Linder as Doctor Latour

Chuck Connors as Captain McCloud - HMS Nereid

George Kennedy as Admiral Conway

Olivia Hussey as Marit

Edward James Olmos as Captain Lopez

Isao Natsuyagi as Commander Nakanishi

Julie Khaner as Secretary - Palmer Station

George Touliatos as Col. Rankin

Sonny Chiba as Dr. Yamauchi

Tsunehiko Watase as Yasuo Tatsuno

Kensaku Morita as Ryûji Sanazawa

Toshiyuki Nagashima as Akimasa Matsuo

Nicholas Campbell as Radio Operator - Palmer Station

Chris Wiggins as Dr. Borodinov

Eve Crawford as Dr. Irma Ollich

John Bayliss as Major King

John Rutter as Sailor #1 - HMS Nereid

Alf Humphreys as Sailor #2 - HMS Nereid

Michael Tough as Young Sailor - HMS Nereid

Ken Ogata as Prof. Tsuchiya

William Binney as White House Aide Simmons

Stuart Gillard as Dr. Ed Meyer

Colin Fox as Spy Z

Ken Pogue as Dr. Krause

Alberta Watson as Litha (uncredited)

Danielle Schneider as Secretary - Palmer Station

Mitsuko Oka as Tatsuno Yoshiko

Takashi Noguchi as Doctor's Assistant

Nenji Kobayashi as Doctor's Assistant #2

Haruki Kadokawa as Crew Member

Chū Takatsuki as Crew Member

Takeshige Hatanaka as Crew Member

Chikara Gonoue as Crew Member

Danielle Schneider as American Antarctic Crew Member