Thirty-eight-year-old Jason Crist of Pacifica was charged with assaults on three women.
"We have accused him of sexually assaulting. Was through the methodology -- befriending them, working with them in the rock-climbing arena and then eventually getting them alone and, by our allegations, sexually assaulting them," said San Mateo County District Attorney Stephen Wagstaffe.
Wagstaffe is concerned there may be more victims.
Crist pleaded not guilty to nine felony sexual assault charges after appearing in San Mateo court Wednesday morning.
MORE: Police searching for Mountain View barber charged for sexually assaulting 2 men
Crist, a former instructor at Movement climbing gym in the Presidio, is accused of assaulting the women between 2019 and 2023 in Pacifica, the Presidio, at Joshua Tree and in Yosemite. The survivors include a Movement employee and member.
"He ignored their demands to say no and assaulted them," Wagstaffe said.
Wagstaffe explains how he knew the victims.
"He is a teacher of rock climbing, apparently has quite a legacy around the world of being an expert at climbing," Wagstaffe said.
"He worked at a local gym for years and is involved in outdoor activities. He is a brand ambassador for some large climbing brand," said Kimberly Harrison, president of Bay Area Climbers Coalition.
MORE: New images capture violent attack on employee at SF Safeway; suspect charged with 2 felonies
After Wednesday's hearing, Crist was released on a $500,000 bail.
ABC7 News tried to reach him at his home but had no luck.
One victim told ABC7 News she's been climbing for more 10 years and was assaulted more than once by Crist in Pacifica and Presidio. She said she filed several complaints with police and the climbing gym.
Other victims say they were assaulted when they were climbing outdoors.
Members of the climbing community were in court today to support the survivors, including Harrison.
MORE: Man arrested for alleged vicious attack on female Safeway employee in SF: police
"You place your trust in your climbing partner, whether you are an expert or novice. You need to know that person will save your life when necessary so that does open you up to exploitation," said Harrison. "The climbing community is really looking inward now to see how we can respond to these issues. Clearly, this is not the first case to come up."
Kimbrough Moore has written several guidebooks on climbing.
"This is the second major sexual assault case in Northern California in the last two years," Moore said. "Two years ago, there was a famous climber who was convicted of sexual assault. He's actually serving a life sentence right now -- Charlie Barrett."
Moore says the allegations against Crist are deeply disturbing.
"Joshua Tree and Yosemite are two of the largest climbing areas in the world. And really special places for some people. The thought that somebody could take those really sacred pieces of land and harm someone in them is really incomprehensible to me," Moore said.
The attorney representing Crist did not comment today. Crist is out on bail. He'll be back in court on Dec. 16.