At the time of its release, Beneath the 12-Mile Reef was considered more notable for its technical achievements than its artistic virtues, a judgment that is still valid, up to a point. It wasn't the most earth-shattering drama ever made, though the performances seem better than they were probably given credit for being at the time. 20th Century Fox's second Cinemascope production starred Robert Wagner (at the height of his male ingénue phase) and Terry Moore in a modern Romeo and Juliet story. He plays Tony Petrakis, the cocky but good-hearted son of Greek sponge fisherman Mike Petrakis (Gilbert Roland), who fishes the area off the Florida coast. The fiercest rivals of Petrakis and his fellow Greek fishermen are the English-descended hook-boat fishermen -- led by Thomas Rhys (Richard Boone) -- who are prepared to kill anyone who intrudes on their established territory. Mike Petrakis has already had one run-in with Arnold, a protégé of Rhys' and the would-be husband of Rhys' daughter, who doesn't know when to back off. In the midst of their conflict, which has come close to gunshots being exchanged, Tony meets Gwyneth Rhys (Terry Moore), Thomas' daughter. She's fascinated by this handsome young Greek who doesn't seem afraid to fight back against men bigger, older, and tougher than he is. The two end up falling in love, much to the consternation of their two families and their friends. Mike later dies in a tragic diving accident, in the aftermath of which his boat is looted and burned at the instigation of Arnold. The elder Rhys turns out to be a better and fairer man than Arnold, who mercilessly beats Tony after catching him off guard. Tony and Gwyneth end up running off together in her hook-boat, with Arnold and her father in hot pursuit, ready to kill him. Only Thomas Rhys' basic decency and Tony's bravery -- coupled with Arnold's cowardice, lust, and anger -- manages to get the conflict settled, in a surprising (and convincing) resolution.
~ Bruce Eder, All Movie Guide