After a broken race ski derailed his spring plans, the 25-year-old RMI guide pivoted to the trail—shattering the unsupported, on-foot round-trip record by a massive 31 minutes.
Simon Kearns, 25, has been training as a mountaineer and guide since he was 12 (Photo: Simon Kearn)
Published May 21, 2026 02:44PM
At just 25 years old, mountaineer Simon Kearns has already built an impressive résumé, including speed records on Mount Hood and Mount Massive. On May 9, the professional guide added another milestone: shattering the previous unsupported, on-foot record of Mount Rainier by more than 30 minutes.
Kearns completed the 14.5-mile round-trip fastest known time (FKT) to the mountain’s 14,411-foot summit and back in 3 hours, 43 minutes, and 52 seconds. He covered roughly 9,000 feet of vertical gain along the way.
“I put a lot into this record training for it, and failed a couple of times. Getting down and knowing that I was finally done, I was really happy, and realized I could finally rest,” Kearns told Outside. “I was definitely crying—disbelief that it had gone so well. I didn’t think I would beat the record by so much.”
The previous round-trip record, set by Alex King in June 2021, was 4 hours, 14 minutes, and 13 seconds. And setting the running record wasn’t even Kearns initial plan: he originally wanted to set a ski record on America’s fourth-highest mountain. But a year of lean snow and a broken ski derailed his initial goal.
“I’m more of a skier than a runner, and I really wanted to break the ski record. But the week leading up to my attempt, I snapped my ski in half—it was the only pair of skis I had at the time,” Kearns said. “Because it was a super dry winter on the mountain, it made more sense to pivot to running.”
As an unsupported on-foot attempt, Kearns was only allowed to bring whatever supplies he could carry. He wasn’t allowed any outside assistance, crew, or resupply. His kit consisted of lightweight running shoes, microspikes, thermal layers, a crevasse rescue kit, emergency items, a helmet, and ski poles.
According to Fastest Known Time, the website that tracks FKT records, the most common line starts at the Paradise parking lot. The route then climbs the Muir Snowfield, a permanent patch of snow, to Camp Muir, and then ascends the snowy Cathedral Gap to the Ingraham Direct, Camp Comfort, and on toward the summit crater. This time of year, the route is mostly snow-covered and requires glacier travel.
Kearns started guiding for Rainier Mountaineering Inc. (RMI), a mountain guide company based in Ashford, Washington, in 2025. According to the outfitter, the San Juan, Colorado, native already has 15 Rainier summits under his belt, including the new car-to-car best time of 4 hours, 18 minutes. He also holds FKTs on Mount Hood and Mount Massive, summits of Mont Blanc, the Grand Teton, and 33 of Colorado’s 58 14ers. In early May, Kearns also set an FKT on Mailbox Peak outside of Seattle.
Kearns said accomplishing an FKT is a testament to his 13 years of training and working in the mountains. His new record is one in a long history of those set by mountaineers at the mountaineering company he guides for, RMI.
“Speed records on Rainier go back decades, usually done by mountain guides on their days off. The guides know the route and conditions intimately, and know when conditions are ripe for a speed attempt,” FKT wrote.
Lou and Jim Whittacker, along with fellow mountaineer John Day, set the first documented Mount Rainier record in 1959. They clocked the route at 7 hours, 20 minutes. According to RMI, records are almost always set by guides, climbers, and athletes.
Kearns said he’s super tired, stoked, and ready for the next challenge.
“I’m primarily focused now on guiding, but I’ll race on the side,” Kearns said. After that, he hopes to get his FKT on Long’s Peak, a 14,259-foot mountain in Rocky Mountain National Park.
