The plot [by Beverley Cross and Raqy Harryhausen] takes Patrick Wayne, as Sinbad, on a quest to free a prince (Damien Thomas) from the spell of evil sorceress Margaret Whiting. Thomas has quite a dilemma, in that he’s turned into a baboon and is fast losing all vestiges of human behavior.
Along for the odyssey are a couple of young cuties (Taryn Power and Jane Seymour) who keep their modest demeanor while wearing scanty outfits.
The plot scenes are hammy beyond belief. Whiting is a particular offender with her all-stops-out villainy.
When the fantasy creatures have center stage, the film is enjoyable to watch. Such beasties as skeletons, a giant bee and an outsized walrus, are marvelously vivified by Ray Harryhausen.
Most of the studio work was done in England, with locations in Spain, Malta, and the Mediterranean.