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)