Rod Taylor

Character: H. George Wells

Alan Young

Character: David Filby / James Filby

Yvette Mimieux

Character: Weena

Sebastian Cabot

Character: Dr. Philip Hilyer

Tom Helmore

Character: Anthony Bridewell

Whit Bissell

Character: Walter Kemp

Doris Lloyd

Character: Mrs. Watchett

Bob Barran

Character: Eloi Man (uncredited)

Paul Frees

Character: Talking Rings (voice) (uncredited)