The submarine scenes were shot in a real submarine in Long Beach, California.
City officials refused to allow the filmmakers to shoot on the real Golden Gate Bridge, because they didn't want the public to think that the bridge could fall. Ray Harryhausen recreated the entire bridge in miniature.
Because the budget was so low, Ray Harryhausen saved money by building his octopus model with six rather than the correct eight tentacles. He tried to pose the creature so this lack of the right number of arms wasn't apparent.
This is the film that brought together producer Charles H. Schneer and special effects legend Ray Harryhausen. Their professional relationship would last until Furia de titanes (1981), the final feature for both men.
Kenneth Tobey completes a military trifecta in this movie. In El enigma de otro mundo (1951) he played an Air Force Captain, in El monstruo del mar (1953) an Army Colonel and in this a Navy Commander.