The Wildflower Triathlon was a triathlon (swim-bike-run race) held at Lake San Antonio in Central California from 1983 to 2019, the first winner being Dean "The Machine" Harper. It was held the first weekend in May each year.
The original course was expanded to the standardized half-Ironman distance (1.2 mi / 56 mi / 13.1 mi) in the late 1980s, and was often referred to as simply the long course. Two more races were subsequently been added to the event: an Olympic-distance (1.5 km / 40 km / 10 km) race and a short or "sprint" mountain-bike triathlon (0.25 mi / 9.7 mi / 2 mi).
Known for a particularly hilly and grueling course, it was one of the largest triathlon events in the world, with 7,500 athletes and 30,000 spectators attending each year at its peak. Traditionally it was associated with a Wildflower festival, though in later years the festival had been eclipsed by the increasingly large athletic event. A drastic drop in lake level in 2014 led to a modified course[1] and lower attendance.[2] Shortly after the 2015 event, the Monterey County Board of Supervisors announced it would close Lake San Antonio due to low water levels.[3] The event was canceled in 2017 and 2019. It was canceled in 2020 due to the COVID-19 pandemic. In July 2023 it was announced that a new triathlon not associated with the previous Wildflower Triathlon would be held at the site.[4] Wildflower organizers have announced their plans to bring back the race in May 2025.[5]