Those shots of Fabian, Peter Brown and Tab Hunter--photographed from mid-chest up--riding their surfboards were actually shot on a sound stage at Columbia Studios. The actors balanced on Radio Flyer wagons in front of a rear-projection screen showing ocean waves. Assistants then sprayed them with water while maneuvering the wagons to give the desired effect.
The Tab Hunter character "Steamer Lane" was named for the world-class surfing spot in Santa Cruz, Calif. Surfing pioneer Jack O'Neill tested and improved his invention, the neoprene wetsuit, at Steamer Lane in the '50s. The O'Neill Coldwater Classic competition has attracted the world's top surfers to The Lane annually since 1987, with a $425,000 prize purse in 2012.
The first feature film directed by TV-veteran Don Taylor. When his mother died during filming, Columbia brought in Phil Karlson to direct a few scenes (uncredited) in Taylor's absence. According to Tab Hunter's autobiography, Karlson directed the scene in which Hunter assures his future mother-in-law that he's not a beach bum but rather a hard-working citizen. Producer Art Napoleon also directed some scenes uncredited.
The Waimea footage in the movie was actually shot by the Napoleons, who traveled to Hawaii specifically to capture surfers taking on the giant waves. A series of weather conditions had come together to produce one of the longest uninterrupted periods of big waves in recent memory in late 1962 through March 1963. The Napoleons, equipped with these spectacular shots, went back to California and wrote the script around them.
Despite pulling Jan and Dean from the movie, Columbia had no problem keeping in their closing song, "Ride the Wild Surf", co-written by Jan, Beach Boy Brian Wilson, and famous surf lyricist Roger Christian. The song went to #16 on Billboard's Top 100 on October 31, 1964,