Prof. Clete Ferguson
Helen Dobson
Joe Hayes
Captain Lucas
Jackson Foster
Lou Gibson
George Johnson
Police Captain
Woman on Boat (uncredited)
Patrol Boat Dispatcher (voice / uncredited)
Photographer (uncredited)
The Gill Man (in water) / Lab Technician (uncredited)
Miss Abbott (uncredited)
Cop (uncredited)
Jennings (uncredited)
Skipper (uncredited)
Cop (uncredited)
Pete (uncredited)
Mac - Spotlight Party Leader (uncredited)
The Gill Man (on land) / Marineland Diver (uncredited)
Diver (uncredited)
Charlie (uncredited)
Newscaster (uncredited)
Police Announcer (uncredited)
Dr. McCuller (uncredited)
Girl in Convertible
Search Party Member (uncredited)
Policeman (uncredited)
Joe (uncredited)
Man at Tank (uncredited)