Courtney Dauwalter throws down 2:38 marathon in an aerodynamic prototype
The shoe helped Dauwalter cut 11 minutes off her marathon best in two months
Michel Cottin/UTMB
In case you missed it, the greatest female ultra-trail runner in history, Courtney Dauwalter, made a rare appearance on the roads last weekend at the 2025 California International Marathon (CIM) in Sacramento, Calif.
Dauwalter stormed to an 11-minute personal best of 2:38:55, cracking the top 75 at the USATF Marathon Championships, and did so wearing a never-before-seen Salomon road-racing prototype. The shoe appears to be the newest iteration of Salomon’s carbon-plated Phantasm S/Lab line, featuring a redesigned upper reportedly engineered to be the most aerodynamic road racing shoe out there.
The mystery shoe first surfaced on Instagram via @the_secret_shoe last week, where one commenter wrote they had tried the model at The Running Event (TRE) in San Antonio. According to their firsthand impressions, the upper features a micro-knit, lace-covered design intended to reduce drag and smooth airflow over the foot, something not often seen in road racing shoes.
As a shoe nerd myself, I can’t help but question whether aerodynamics really matter when someone is moving at less than 20 km/h. And in Dauwalter’s case, if the rest of the race day fit isn’t optimized for resistance (like her iconic oversized trail shorts), does having aerodynamic features really make a difference?
Beyond the upper, the Phantasm prototype reportedly features a new foam blend midsole with more rebound and what appears to be an updated EnergyBlade carbon plate sandwiched inside. Whatever Salomon changed in this latest iteration, it clearly worked as Dauwalter cut 11 minutes off her marathon best just two months after running 2:49:51 at the Twin Cities Marathon in early October.
“I already know I’ll need to try this distance again,” Dauwalter wrote on Instagram after her marathon. “It feels so different from what I’ve been doing for the past years, and I’m excited to keep building on that.”
Her CIM performance put her a minute and 55 seconds shy of the U.S. 2028 Olympic Trials marathon standard of 2:37:00. But trail fans shouldn’t expect the 40-year-old to pivot to road racing anytime soon.
There has been no word yet on when this Salomon road racing prototype will reach the market, but it may appear on the feet more Salomon athletes in the coming months.
