Set for Saturday, June 6, 2026, the Green River Marathon, Relay, Half Marathon, and 50K invites runners to experience a low-key, community-focused event in Kent, WA. Celebrating its 30th annual running, this race distinguishes itself as a donation-based event, with proceeds benefiting Northwest Harvest and local food banks. Runners can choose from a full marathon (26.2M), a half marathon (13.1M), an ultra-distance 50K, or join friends for the marathon relay. Typical race day conditions in early June offer pleasant temperatures, with highs around 70°F and lows around 52°F, and only a 7% chance of precipitation.

The race kicks off and concludes at the Three Friends Fishing Hole in Kent, WA, utilizing an out-and-back course along the scenic Green River Trail. The terrain is notably flat, offering an excellent opportunity for personal bests. Half marathoners complete two out-and-back segments, marathoners tackle four, and 50K participants extend their journey with an additional 2.4-mile out-and-back after their four marathon loops. Each standard out-and-back segment covers 3.28 miles, with all runners initially heading south on the trail. Aid stations are strategically placed approximately every 6.55 miles, providing water, Gatorade, and various snacks to keep participants fueled. Runners are encouraged to bring their own water bottles, as cups are not provided.

What truly sets the Green River Marathon apart is its welcoming atmosphere and flexibility. Participants benefit from a generous start window between 5:15 AM and 9:00 AM, allowing runners to begin when it best suits their race strategy. While it's a self-reported timing event, it has historically been recognized as a Boston Marathon qualifier. The focus remains on the joy of running and contributing to a worthy cause, making it a beloved event for runners seeking a supportive environment and a flat, fast course in the Seattle area.