Welcome to the 2025 Seafair Triathlon! 

Seattle's only triathlon will once again take place on the shores of Lake Washington at Seward Park. Offering 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 distance 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. 

Offering a Kids Triathlon as well, there is a distance for everyone in the family at the Seafair Triathlon! Join us in July for the 2025 Seafair Triathlon with over 1,500 health enthusiasts taking part in the event.

Seafair Tri Info

The Seafair Triathlon, offers participants multiple disciplines on a flat, fast and picturesque triathlon course only 10 minutes from Downtown Seattle at Seattle’s Seward Park. Seattle’s ONLY Triathlon will once again take over the shores of Lake Washington this summer and Seward Park is the perfect backdrop for this flat, fast and picturesque triathlon course in the shadows of Downtown Seattle.

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

Offering a Kids Tri as well, there is a distance for everyone in the family at the Seafair Triathlon! Join us at the Seafair Triathlon with over 1,500 health enthusiasts taking part in the event.

Schedule

5:30a.m. – Transition Zone Opens

6:00a.m. – Race Day LATE packet pickup & body marking begins

6:00a.m. – Bike Mechanics Area Opens

7:00a.m. – Sprint Triathlon Course Start

7:21a.m. – Sprint Relay Team Swim Start

7:35a.m. – Duathlon Bike Start

7:48a.m. – Super Sprint Course Start

10:30a.m. – Kids Short Course Start

11:00a.m. – Kids Long Course Start

Course Information

Race Distances

Sprint Distance Triathlon – 0.5 mile swim, 20K bike ride, 5 Kilometer run

Sprint Duathlon – 20K bike ride, 5 Kilometer Run

Sprint Distance Relays – Same as the sprint course

Super Sprint Distance Triathlon – 0.25 mile swim, 20K bike ride, 5 Kilometer run

Kids Long Course – 100-yard swim, 2-mile bike ride, 1-mile run

Kids Short Course – 50-yard swim, 1-mile bike ride, 0.5 – .75 mile run (swim in water kids can touch in)

Swim Course – Counter-clockwise swim in the protected cove of Andrews Bay at Seward Park in Lake Washington (1 full triangular lap for sprint, 1 smaller triangular lap for super sprint) The cove is protected from wind and boats. There will be lifeguards onsite if a rest is needed or to help you safely finish the swim

Bike Course – Sprint Distance, Super Sprint, Relay Teams and Duathlon participants will ride north through along Lake Washington Blvd through multiple waterfront neighborhoods including Leshci, Madrona and Madison Park. All participants will follow LWB, connecting to McGilvra, then looping around the Madison Park neighborhood before returning to Seward Park. With only one hill, this is a fast course for all cyclists!

Run Course – All participants will complete one loop around Seward Park from the swim beach to the south side of Seward Park. Midway through your run, participants will run out and back to the upper loop of Seward Park before finishing at the south parking area where the post run celebration waits! The run course is the same for all Sprint, Super Sprint and Duathlon participants.

Swag!

All participants of the Seafair Triathlon (both kids & adults) will receive the following, included with race registration. If registering as a team, each member will receive a shirt and medal!

Seafair Triathlon participant shirt

Event Finisher Medal (Adults & Kids!)

FREE downloadable participant photos (average of 4+ per participant)

Timing Chip, Swim Cap

Unique Race Bib

Cost: $35 - $115

Register Here