The working title of this film was Mr. Co-ed. According to an unidentified source in the file for the film at the AMPAS Library, the original story was titled "Sink or Swim." Excerpts from Xavier Cugat's "Thrill of a New Romance" and Carlos Ramirez and Harry James's "Boogie Woogie" are heard during the water ballet sequence. In the film, Red Skelton does an extended, comic impression of a woman waking up and dressing. Ethel Smith, a popular organist who performed on the radio show The Hit Parade, made her screen debut in the film. Smith was later featured in several additional M-G-M films.
       In late 1940, M-G-M announced plans to shoot a film entitled Mr. Co-ed, starring Marjorie Main, Myrna Loy and William Powell and directed by Jack Conway. According to HR news items, Palo Alto and Berkeley, CA, were scouted as possible locations for that production in Dec 1940, but because of script problems, the project was shelved in early Jan 1941. It has not been determined whether the 1940 Mr. Co-ed project was in any way related to the 1944 Bathing Beauty.
       HR news items provide the following information about the production of Bathing Beauty: In Feb 1942, Irving Starr was assigned as the film's producer. In Sep 1942, Harry Clork was hired to write the screenplay, but his contribution to the completed film has not been confirmed. Songwriters Don Raye and Gene de Paul were originally signed to write the film's numbers, which were to feature Phil Spitalny's all-girl orchestra, and Lennie Hayton was to score the picture. Jimmy McHugh and Al Dubin were then hired to write songs with a "Latin-American flavor" for Ramirez and Cugat. Although Janis Paige was to sing "How Can I Hold You Close Enough" by Johnny Green, that number was not included in the final film. Swimming sequences were filmed at the Lakeside Country Club in Toluca Lake, CA. According to a Life magazine spread about the production, a special crane was used for the water ballet sequence to allow the camera to move horizontally and vertically at the same time. For underwater shots in the 90-foot pool, the camera was encased in a specially constructed "aquachamber," which resembled a phone booth. M-G-M makeup artist Jack Dawn adapted an "ancient Chinese invention" to create the first "waterproof coiffure" for the production, which reportedly enabled the swimmers to dive into swimming pools without damaging their elaborate headdresses. (Modern sources claim, however, that Vaseline petroleum jelly was applied). According to a M-G-M publicity item, makeup artist Benny Libizer designed for the film a makeup applicator called an "aquapuff," which was used to apply waterproof, liquid makeup to the swimmers between shots.
       According to HR, M-G-M dance instructor Joe Hickey was to perform a featured dance number in the picture, but his appearance in the final film has not been confirmed. HR news items list the following actors as cast members: Florence Lundeen, Peggy O'Neill, Frances McInerney, Pat Hogan, Florence Turner, Marion Ackerson, Barbara Brewer, Valeria Brownell, Bonnie Jean Hartley, Carol Sawyer, Ethel Sherman, Gloria Sherwood, Diana Cannon, Ruth Harrah, Margaret Greene, Marilyn Perkins, Frances Eilerson, Molly Ann French, Barbara Heglar, Catherine Livingston, Edith Pemberton, Adele Peterson, Shirley Schubert, Kay Shaw, Earlynne Waterston, Barbara Gagnon, Marek Windheim, Kay Adell, Blanche Ames, Colleen Bisson, Jean James, Betty Mills, Doris Munyon, Elinor Skube, Gwen Spaulding, Margaret Thompson and Florence Warner. Their appearance in the completed film has not been confirmed, however.
       An Oct 1943 M-G-M publicity item announced that the following "schoolgirls" from San Diego and La Jolla, CA swim teams were "discovered" in Los Angeles and were cast in the picture: Kay Rice, Margaret Pugh, Pat Dunlap, Mela McGonigal, Marjorie Bolinger, The Browne Twins and The Farnham Twins. According to a HR news item, the Nerwin Uniswimmers were featured in the water ballet sequence. In addition, publicity items note that Martha Winter, who had held the all-time record for underwater swimming, was to make her screen debut in the water ballet sequence. The participation of these swimmers in the final film has not been confirmed, however.
       Although not her debut film, Bathing Beauty marked Esther Williams' first Technicolor musical. According to HR, Bathing Beauty was the first of three M-G-M films to be dubbed into Spanish for Latin American release. (Gaslight and The White Cliffs of Dover were the other two.) Xavier Cugat and Carlos Ramirez appeared in a Spanish language trailer for that release. "Tico-tico, No fubá" a Latin number played in the picture by Ethel Smith, became a hit record after the film's release.