Diamond Mountain Triathlon
Always double-check with the organizer's website! This page may contain affiliate links.
Diamond Mountain Triathlon (USAT Sanctioned)
The Diamond Mountain Triathlon takes place on September 20, 2026, at Lake Welch Beach in Harriman State Park, Stony Point, NY. The venue uses Lake Welch for the swim and park roads for the bike and run courses.
The triathlon course includes a 0.5 mile swim in Lake Welch, a single 15 mile bike lap around Harriman Park, and a 2 mile run on paved road with some gravel sections. The duathlon uses two 2 mile runs with the same 15 mile bike lap. Transition is at the Lake Welch picnic area.
- Triathlon: 0.5 mile swim, 15 mile bike, 2 mile run
- Duathlon: 2 mile run, 15 mile bike, 2 mile run
Racing is offered in multiple waves. Elite and advanced athletes are placed in early waves; Open and Family athletes start in a later wave where personal buoys are allowed. Junior athletes are scored with adults, start by default in the later wave, and may request an earlier wave before registration closes. Junior entries for triathlon and duathlon are free. Typical adult registration fees are listed as $110 for triathlon and $90 for duathlon.
Event services include police controlled intersections, course signage, volunteer support, race photographers, free public parking, open restrooms, and water at check in. Finisher medals are provided to all participants. Top three men and women in each race receive awards; age group awards depend on turnout. Triathlon participants receive a free jersey, duathlon participants receive a running jersey, and overall adult triathlon winners receive a triathlon suit. Wetsuits are welcome. Any safe, working bike may be used; no rental bikes are provided. Official results and photos are normally available within 48 hours. Visit the organization's website for the most recent information.
