2025 Seafair Triathlon

The Seafair Triathlon, Seattle’s ONLY triathlon is waiting for you to join us in 2025!

This Lake Washington triathlon offers participants multiple disciplines on a flat, fast and picturesque triathlon course in the shadows of downtown Seattle. This race is a must do for all triathletes in the Northwest.

The event offers participants a unique opportunity to participate in a sprint distance triathlon or super sprint triathlon in an urban setting. Swimming in a protected cove, riding on closed roadways, and running through Seward Park, this is the Pacific Northwest’s premier triathlon.

Are you a beginning triathlete? We have options for you as well including a "Super" Sprint Triathlon featuring a short, 0.25 mile swim, 14-mile bike and 5K run, duathlon (bike & run) and relay options for people trying to master one or more disciplines!
The Seafair Triathlon also features the biggest kids triathlon around as part of the day's events. Two different kids waves for the big kids, we have a real swim, for the littler kids, a wading division that finishes with a bike ride, then a sprint to the finish!
There's a distance for everyone in the family at the Seafair Triathlon!

Sprint Triathlon - .5-Mile Swim, 14-Mile Bike, 5K Run
Sprint Duathlon - 14-Mile Bike, 5K Run
2 & 3 Person Team Triathlon - .5-Mile Swim, 14-Mile Bike, 5K Run
Super Sprint Triathlon - .25-Mile Swim, 14-Mile Bike, 5K Run

Also check out other Sports events in Mercer Island.