Admiral Michael Matthews

Stuart Whitman

Brett

Robert Wagner

Lia Holmes

Rosemary Forsyth

Commander Woody Patterson

Robert Colbert

Eleana

Susana Miranda

Aguila (as Burr De Benning)

Burr DeBenning

Dr. Ziegler

Joseph Cotten

Barton

Paul Stewart

The President

Richard Basehart

Dr. Talty

James Darren

Professor Holmes

Whit Bissell

Capt. Hunter

Sugar Ray Robinson

Bill Holmes

Larry Pennell

Gen. Putnam

Tom Drake

Quinn

Charles Dierkop

Burr de Benning

Capt. Lunderson

William Bryant

Young Officer

Robert Dowdell

Dr. Burkson

Edward G. Robinson Jr.

Blonde Woman

Sheila Mathews

Tony

Johnny Lee

Sally

Glenna Sergent

Triton Controller

Erik L. Nelson

Triton Controller

Erik Nelson

Scientist (uncredited)

Paul Bradley

Scientist (uncredited)

George Holmes

Scientist (uncredited)

Victor Toyota