The average California surfer, studies show, is about 35 years old, college-educated and making $75,000 a year, enough income to own, on average, four surfboards.

The typical surfer isn’t a low-income, Muni-riding San Francisco high school student who recently learned how to swim.

Yet more than 100 teenagers from the Mission, Western Addition and other neighborhoods across the city are becoming part of the Bay Area’s surf scene, learning to catch waves and earning gym-class credit while wearing a wetsuit.

Surfer and former teacher Johnny Irwin founded the City Surf Project four years ago, realizing that most urban kids — even those who live within a few miles of the ocean — don’t surf. But they want to, he said.

“Our youth are entering that surf scene, youth of color,” Irwin said.

Miguel Pastreich went surfing with the program his freshman year at Mission High School. Now a junior, he’s one of the more experienced surfers, often taking his board on Muni and riding waves before school.

“I grew up in San Francisco my whole life and would never go to the beach,” he said. “As soon as I started this, I’ve been at the beach all the time.”

In the water, the kids are finding a sense of self, a calmness and confidence that they don’t always find on the streets, said Ray Sotto, community health outreach worker for the San Francisco school district.

“For at-risk youth, they get to the beach and they’re kids again,” said Sotto, who also surfs with the students. “They leave everything behind.”

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The nonprofit program works with several city schools, providing equipment, instructors and transportation for physical education classes and school surfing clubs.

After proving they can swim, students learn how to paddle, get up on a board and fall. They absorb surfing etiquette as well as the science of tides and why some places, at some times, see bigger and better waves, Irwin said.

At Mission High, it’s the most popular PE class, students said.

The day before winter break, a handful of the school’s surfing club members piled into the City Surf Project van, boards piled on top and wetsuits filling the back, and headed 60 miles south along Highway 1 for an official field trip.

They parked along the cliffs in Capitola, put on their suits and headed into the water — thoughts of schoolwork, family problems, street violence and other struggles forgotten.

“I definitely feel that I’m less stressed out when I go to the water,” Patreich said.

The City Surf Project operates on $300,000 a year, with city funding, private donations and a state Coastal Conservancy grant helping pay costs.

Surfing can be expensive and thus inaccessible, Irwin said, requiring a board, a wetsuit and transportation to where the waves are. Aside from the costs, the pastime can be a foreign concept to the kids, who often don’t know anyone who surfs. The activity is outside their comfort zone.

“You could say the same thing about going to college for a lot of these kids,” said Leo Maxam, a volunteer with the program.

Convincing them they can surf opens up a world of possibilities, he added.

“A wave doesn’t care who you are, where you’re from, what color you are or how much money you have in the bank account,” Maxam said. “Surfing creates such strong friendships and bonds, and now these kids are starting to enjoy that.”

To help support the program, professional surfing photographer Nate Lawrence is working on a book, “City Surf,” documenting the students and the city where they live, while raising funds through Kickstarter.

After seeing the students’ faces light up in the water, Lawrence said he knew he wanted to capture that.

The program “just spoke to me,” he said. “I wanted to tell these kids’ stories through the photos of San Francisco.”

Currently, about 100 students participate at one of six schools in what Irwin believes is a unique collaboration between a surfing program and public schools.

Irwin doesn’t expect many of the students will become professional surfers, but he does believe the sport will teach them how to face challenges.

Surfing, like life, requires perseverance, with a lot of falling and tumbling in rough waters, he said.

“Surfing is ripe with analogies to life,” Irwin added. “You can’t stop the waves. But you can learn how to surf.”

Jill Tucker is a San Francisco Chronicle staff writer. Email: jtucker@sfchronicle.com Twitter: @jilltucker