A scientist (George Rowe) is looking for a type of pearls. He has a rival (Timothy Carey) and gets involved with various mermaids well, topless women who swim under water. That’s in the later “nude edition” of this film. In the original 1962 edition there was less nudity – flashes of bare back mostly, plus shell bras.
The underwater photography is top quality and the woman attractive. This could be the best-shot film ever released by Roger Corman’s Filmgroup. At first it’s like “this is pretty hot, all these gorgeous women frolicking”. They frolic and frolic some more… and then after a while you start to wish something would happen. Carey turns up to be evil but he’s not that evil and it’s not exciting. None of the mermaids speak (there’s very little dialogue – most of it is done via narration.) The hero doesn’t even have a romance with a mermaid which I’m sorry is just crap. (In the original version – the one issued by Filmgroup, focuses on one mermaid, who has a fin and everything. But the director made a new edition where he added a bunch of topless swimmers without fins.)