Port Sinister known as Beast of Paradise Isle in the UK is an adventure

Adventure

An adventure is defined as an exciting or unusual experience; it may also be a bold, usually risky undertaking, with an uncertain outcome. The term is often used to refer to activities with some potential for physical danger, such as skydiving, mountain climbing and or participating in extreme sports...

/science fiction

Science fiction

Science fiction is a genre of fiction dealing with imaginary but more or less plausible content such as future settings, futuristic science and technology, space travel, aliens, and paranormal abilities...

 film written by Jack Pollexfen and Aubrey Wisberg

Aubrey Wisberg

Aubrey Lionel Wisberg was a screenwriter, director, and producer.He immigrated to the United States in 1921, attended New York University and Columbia University, and married Barbara Duberstein...

 and directed by Harold Daniels. The plot synopsis consists of a 17th century Caribbean city of Port Royal

Port Royal

Port Royal was a city located at the end of the Palisadoes at the mouth of the Kingston Harbour, in southeastern Jamaica. Founded in 1518, it was the centre of shipping commerce in the Caribbean Sea during the latter half of the 17th century...

 which has been long rumoured to have been visited by pirates rises from the ocean floor.

However, when a scientist goes to investigate the incident -- and at the same time the local thugs plan to steal the gold -- all are attacked by giant crabs living there.

Pollexfen and Wisberg had already made Captive Women

Captive Women

Captive Women is an American Sci-Fi film from 1952. The movie is fairly short, only 64 minutes and is in black-and-white. In 1956 it was re-released by the name 1000 Years from Now. In the United Kingdom the movie is known as 3000 A.D, the film's original title...

and Sword of Venus for RKO. Port Sinister was filmed at the RKO studios with location work at Palos Verdes

Palos Verdes

Palos Verdes is a name often used to refer to a group of coastal cities in the Palos Verdes Hills on the Palos Verdes Peninsula, within southwestern Los Angeles County in the U.S...

California.