Gerard Butler nearly drowned when a 20 foot wave broke on his head whilst filming a scene at Mavericks, California.
Jonny Weston was hired with no prior film or commercial acting work. He was discovered via an audition video he submitted via a casting website where anyone who's looking for modeling or acting work can sign up for, create a profile and audition for work.
Michael Apted directed the last three weeks of principal photography after Curtis Hanson had to pull out for health reasons. When Hanson was proved to be in too poor of health to return, Apted ended up directing all of post-production and completing the final cut without Hanson's involvement.
Gerard Butler was a very inexperienced surfer before taking on his role in the film. Jonny Weston, on the other hand, had been surfing for about 10 years.
Gerard Butler was briefly hospitalized when a surfing stunt went wrong. Part of his recovery involved a heavy course of painkillers. Butler would later check himself into the Betty Ford Clinic to wean himself off these painkillers.
This movie was actually shown on the same beach that is flown over in the first few opening minutes of the film in Mid-August 2013.
Stepping into Curtis Hanson's shoes at such short notice was a daunting experience for Michael Apted. He arrived on a Sunday, and started working the next day with a cast he'd never met, a crew he didn't know and on locations he'd never seen.