- Bill Baldwin - Patrol Boat Dispatcher (voice / uncredited)
- Jere Beery - Photographer (uncredited)
- Ricou Browning - The Gill Man (in water) / Lab Technician (uncredited)
- Diane DeLaire - Miss Abbott (uncredited)
- Mike Doyle - Cop (uncredited)
- Clint Eastwood - Jennings (uncredited)
- Jack Gargan - Skipper (uncredited)
- Charles Gibb - Cop (uncredited)
- Brett Halsey - Pete (uncredited)
- Don C. Harvey - Mac - Spotlight Party Leader (uncredited)
- Tom Hennesy - The Gill Man (on land) / Marineland Diver (uncredited)
- Don House - Diver (uncredited)
- Robert F. Hoy - Charlie (uncredited)
- Ned Le Fevre - Newscaster (uncredited)
- Sydney Mason - Police Announcer (uncredited)
- Robert Nelson - Dr. McCuller (uncredited)
- Patricia Powers - Girl in Convertible
- Bert Stevens - Search Party Member (uncredited)
- Charles Victor - Policeman (uncredited)
- Robert Wehling - Joe (uncredited)
- James R. Wolfe - Man at Tank (uncredited)
- Jack Arnold
- Fred Frank
- William Alland
- William Alland
- Henry Mancini
- Leslie I. Carey
- Hans J. Salter
- William Lava
- Milton Rosen
- Herman Stein
John Agar interpreta a Prof. Clete Ferguson en la película.
Lori Nelson hace el papel de Helen Dobson.
John Bromfield hace el papel de Joe Hayes.
Nestor Paiva interpreta a Captain Lucas en la película.
Grandon Rhodes hace el papel de Jackson Foster.
Dave Willock interpreta a Lou Gibson en la película.
Robert B. Williams interpreta a George Johnson en la película.
Charles Cane interpreta a Police Captain en la película.
Loretta Agar interpreta a Woman on Boat (uncredited) en la película.
Bill Baldwin hace el papel de Patrol Boat Dispatcher (voice / uncredited).
Jere Beery interpreta a Photographer (uncredited) en la película.
Ricou Browning interpreta a The Gill Man (in water) / Lab Technician (uncredited) en la película.
Diane DeLaire hace el papel de Miss Abbott (uncredited).
Mike Doyle interpreta a Cop (uncredited) en la película.
Clint Eastwood interpreta a Jennings (uncredited) en la película.
Jack Gargan interpreta a Skipper (uncredited) en la película.
Charles Gibb hace el papel de Cop (uncredited).
Brett Halsey hace el papel de Pete (uncredited).
Don C. Harvey interpreta a Mac - Spotlight Party Leader (uncredited) en la película.
Tom Hennesy hace el papel de The Gill Man (on land) / Marineland Diver (uncredited).
Don House interpreta a Diver (uncredited) en la película.
Robert F. Hoy interpreta a Charlie (uncredited) en la película.
Ned Le Fevre hace el papel de Newscaster (uncredited).
Sydney Mason hace el papel de Police Announcer (uncredited).
Robert Nelson hace el papel de Dr. McCuller (uncredited).
Patricia Powers interpreta a Girl in Convertible en la película.
Bert Stevens interpreta a Search Party Member (uncredited) en la película.
Charles Victor hace el papel de Policeman (uncredited).
Robert Wehling interpreta a Joe (uncredited) en la película.
James R. Wolfe hace el papel de Man at Tank (uncredited).
Capítulo disponible en las siguientes plataformas:
