Dylan Greiner, 38, was arrested after search warrants served at his home and workplace turned up a large collection of videos of young girls taken both at the surf school and on beaches.
He was arrested on suspicion of lewd and lascivious acts with children and taken to Santa Cruz County Jail, where he is being held on $500,000 bail, police said.
Police said the suspect secretly recorded young girls changing into wetsuits at Santa Cruz Surf School, located at 131 Center St., which he owns and operates.
Officers also found "a multitude of photographs and other video secretly recorded by Mr. Greiner" that focused on girls' breasts, buttocks and genitalia, police said.
According to police, a preliminary search on one of the suspect's computers also revealed thousands of videos secretly capturing girls as young as eight years old on the beach.
At the school, Greiner would befriend students as young as 13 years old and offer them free surf lessons or a job at his business, police said.
Police said Greiner made inappropriate sexual advances toward at least two victims, aged 13 and 14, and took inappropriate photos of them focusing on private parts.
A preliminary investigation shows that Greiner has been pursuing in appropriate relationships with young girls for at least the past four years, police said.
Police said the suspect admitted to taking the secret video footage and photos and to downloading illicit images of 13- and 14-year-old girls.
He also wrote apology letters to the two victims identified by police and to the community for his actions, according to police. Detectives are examining the photos and videos seized during the search warrant operations to identify more victims.
Concerned parents and additional victims are asked to contact the Santa Cruz police detectives at (831) 420-5820.