Lace up for the Longmont Half Marathon and 5K on Sunday, May 3, 2026, offering runners a fantastic spring race experience in Longmont, CO. This event, renowned as Longmont's only Half Marathon, provides a welcoming atmosphere for walkers and runners of all abilities. The course is largely flat, featuring less than 300 feet of elevation change, making it an excellent opportunity for personal bests. You'll primarily navigate 100% concrete surfaces with occasional wooden footbridges, tracing the scenic St. Vrain Greenway as it winds through picturesque city parks and alongside the St. Vrain Creek and Left Hand Creek.

The out-and-back course begins and ends at the Longmont Rec Center at 310 Quail Road, guiding participants through beautiful natural areas with views that capture the essence of Longmont. Aid stations are strategically placed approximately every 2-2.5 miles (or at miles 3, 6, 8, and 11 for the half marathon), providing water and electrolyte drinks, with energy gels available at miles 8 and 11. Restrooms or portojohns are also accessible at various points along the route. Typical race day conditions in early May feature comfortable highs around 65F and lows near 38F, with a minimal 14% chance of precipitation, creating ideal running weather.

Participants can expect a well-supported race, with previous runners praising the clean and wide course. With its shift to the cooler month of May, the Longmont Half Marathon offers an even more enjoyable experience for all.