The film premiered underwater to a group of journalists and others wearing diving equipment. The premiere was prior to the national release date of Feb. 9, 1955, and was held in Silver Springs, Florida.
At a promotional event for the movie, a young Jayne Mansfield was one of several swimmers participating in a underwater skit when the top of her bathing suit came off, which obviously drew attention to her, and not the movie. It is believed that she let this happen on purpose for the free publicity.
"Underwater" was a trouble-filled production. After spending months in Hawaii shooting underwater material, the crew lost a barge full of cameras and equipment worth hundreds of thousands of dollars. They were there during the storm season and the water was so murky, it was decided to continue filming in Jamaica, but the same problem arose. John Sturges didn't like the screenplay and recruited screenwriter Walter Newman to rewrite it as they were about to start shooting.
Approximately 60% of the way into the film, both internal and external scenes are reversed. The cabin of the boat suddenly is reversed and shortly thereafter, the deck scene is also reversed. The name of the boat on the life preserver is a mirror image.
The final hit song to emerge from an RKO feature was the sensual instrumental cha cha, "Cherry Pink and Apple Blossom White" (music by noted French composer Louiguy), performed in the film by Dámaso Pérez Prado's renowned Latin band while Jane Russell danced. Billed as Perez Prado and His Orchestra on the RCA Victor single, Mr. Prado triumphed at the number-one "Billboard" spot for 10 consecutive weeks between April 30 and July 2, 1955. The same year on Coral Records, crooner Alan Dale (who did not appear in the movie) charted with a fourteenth-place vocal version (lyrics by Mack David). A '55 Decca release of the ditty by Guy Lombardo and His Royal Canadians featured vocalist Bill Flanagan. Actually, the song wasn't brand new in 1955. Singles had been on record racks in 1951 from Georgia Gibbs on Mercury, Cindy Lord on the MGM label, and Jimmy Dorsey and His Orchestra, with singers Pat O'Connor and Sandy Evans, on Columbia.