The Northumbrian

The Northumbrian is an ultimate endurance event held in the stunning Kielder Water and Forest, Northumberland. It features full and half Iron-distance triathlons, including a 2.4 or 1.2-mile swim in Kielder Water, a 112 or 56-mile bike ride through scenic valleys and challenging roads, and a marathon or half-marathon run along forest trails. New for 2025 are ultra trail runs: a 50K with 700m elevation and a 20K with 400m elevation.

The event combines breathtaking scenery, adventure, and physical challenge, offering participants on-course support, nutrition, timing, and finisher rewards. It attracts individuals and teams seeking a demanding and scenic endurance experience. Visit the organization's website for the most recent information.