Rod Taylor
H. George Wells
Alan Young
David Filby / James Filby
Yvette Mimieux
Weena
Sebastian Cabot
Dr. Philip Hilyer
Tom Helmore
Anthony Bridewell
Whit Bissell
Walter Kemp
Doris Lloyd
Mrs. Watchett
Bob Barran
Eloi Man (uncredited)
Paul Frees
Talking Rings (voice) (uncredited)