David Graham
Professor Matthew Matic / Lieutenant Ninety / Zoonie the Lazoon / Zodan / Warrior Countdown (voice), Dr. Horatio Beaker / Mitch the Monkey / Herman Gredenski (voice), Professor Matthew Matic / Lieutenant Ninety / Freighter A14 (voice), Grandpa Ebenezer Twink / Hank (voice), Dr. Horatio Beaker / Mitch the Monkey / Morse Operator (voice), Professor Mattew 'Matt' Matic / Lieutenant Ninety / Zoonie the Lazoon / Doctor Baker (voice)
Sylvia Anderson
Doctor Venus (voice), Jimmy Gibson / Miss Chevenitch (voice) (uncredited), Doctor Venus / Eleanor Zero / Jonathan Zero (voice), Jimmy Gibson (voice) (uncredited), Dcotor Venus (voice)
Paul Maxwell
Colonel Steve Zodiac / Mrs Doughty (voice), Colonel Steve Zodiac (voice)
Gerry Anderson
Robert the Robot / Granatoid 1 (voice) (uncredited), Robert the Robot (voice) (uncredited)
John Bluthal
Commander Wilbur Zero / Kazak (voice), Commander Wilbur Zero / Jock Campbell (voice), Commander Wilbur Zero / Doctor Simpson (voice)
Graydon Gould
Mike Mercury / Film Narrator (voice), Mike Mercury / Jason Munroe III (voice)
George Murcell
Professor Rudolph Popkiss / Black Morgan (voice), Professor Rudolph Popkiss (voice) (credit only)
Nicholas Parsons
Sheriff Tex Tucker / Telegraph Operator Dan Morse (voice)
Kenneth Connor
Dusty the Dog / Rocky the Horse / Foreman (voice)
Denise Bryer
Martha 'Ma' Jones (voice)
Michael Holliday
Sheriff Tex Tucker (singing voice) (uncredited)