HUNTINGTON BEACH, Calif.—Father Christian Mondor 
marched across the sand Sunday morning toward the roaring 
Pacific followed by dozens of disciples, some carrying 
surfboards and others with bikini strings peeking out of shirt collars. The 89-year-old removed his white vestments and brown Franciscan habit to reveal a black wetsuit.
The crowd hooted and clapped. "Go Father Christian!" shouted Pedro Castagna, 47, clutching a dripping surfboard.
It was reasonable attire for the "Blessing of the Waves," an annual tradition that now attracts more than 1,000 people to a loose, multidenominational ocean-appreciation service, including Jews, Muslims, Mormons and Tongan singers. Sumo Sato, the burly, white-bearded pastor of the H2O Community Church, also made an appearance.
The unique mix of church and surf was started by the fast-growing Roman Catholic Diocese of Orange County seven years ago as an attempt to appeal to young Catholics and tap into the surfing culture of the region. (Huntington Beach is officially known as Surf City USA after a protracted court battle with Santa Cruz, Calif., that was settled in 2008). The diocese tapped Father Mondor, known around town as the Surfing Priest of Surf City, to oversee the event.
"I thought it was a great idea," Father Mondor said. Plus, he added, "We Catholics bless everything in sight."
Father Mondor, who grew up in Southern California, didn't start surfing until he was 70. Heart surgery several years ago has forced him to cut down on surfing, though he's still an avid and lifelong body surfer. "There's a spiritual side to surfing that's very real," he said.
As the event grew, the diocese handed it off to the Greater Huntington Beach Interfaith Council; the event committee now includes a U.S. Olympic men's swimming coach and Dean Torrence of '60s rock duo Jan and Dean.
Religious leaders around here have learned that the ocean can have a stronger pull than pews on Sunday mornings. "Some of my young guys who miss church will say to me, 'I'm sorry, Reverend, the waves were just too good,' " said the Rev. Tim Philips, with the Pacifica Synod of the Evangelical Lutheran Church in America.
Sunday's event was a chance for church to come to the surfers, said Maneck Bhujwala, a representative of the Zoroastrian community. Mr. Bhujwala said he was there for the fellowship, but not the surfing. "Oh no, not me. I'm too chicken," he said.
With the Pacific churning behind him, the bishop of the Diocese of Orange, Kevin Vann, confessed to the crowd that as a Midwesterner, "I really can't swim too well and with my Irish complexion the sun and I don't get along too well."
The bishop was followed by Rick "Rockin' Fig" Fignetti, a surfing champion and surf-competition announcer with a long ponytail. Mr. Fignetti praised the huge swells caused by recent hurricanes, pointed to the sky and shouted "Thank you, Jesus!"
Before wading knee-deep into the waves, Father Mondor offered a prayer thanking "our lord God, Big Kahuna, lord of the waves" for the ocean and asking Him to keep "us always stoked about the beauty and power of the ocean" and "keep the great white sharks always in their space."
Father Mondor didn't surf, deciding to play it safe in rough waters. Marine safety officials urged all but the most experienced surfers to stay out of a ripping current and 6-foot swells.
"Bishop, I know you've got some friends upstairs," Huntington Beach Marine Safety Lt. Michael Beuerlein told him, "but I'm not gonna let you go out there today."
The event had its desired impact as a magnet for the young. Fourteen-old Elizabeth Bennett dipped her feet in the sand with her mother, Peggy, as Father Mondor posed for photos with admirers. The pair, from nearby Tustin, attended the event for the first time. "I did not expect the priest to be wearing a wetsuit," Elizabeth said.
Write to Tamara Audi at tammy.audi@wsj.com