About This Race
The 100K represents Ultra-Trail Snowdonia's ultimate endurance test, demanding runners navigate the full spectrum of Snowdonia's technical mountain terrain over a distance that pushes beyond typical ultra territory into expedition-level commitment. This distance requires exceptional preparation and experience with extended time on technical ground, as runners must maintain focus and composure through challenging navigation and weather exposure across multiple mountain ranges. Best suited for seasoned ultra runners seeking a significant step up from 50-mile distances, the 100K offers the complete Snowdonia experience with extended night running and the mental fortitude needed to persist when the Welsh mountains test every aspect of mountain running skill.
Practical Info
Variable mountain conditions typical of North Wales in May, with potential for rain, wind, and temperature changes with elevation
MAN - Manchester Airport
Llanberis offers various accommodation options from B&Bs to hotels, with additional lodging available in nearby Snowdonia villages
Best For
Notable Features
As part of the UTMB World Series, this race maintains the highest standards of organization and course design. The event showcases the dramatic landscapes of Snowdonia National Park through technical single track that demands both fitness and technical skill. The multi-day format creates a festival atmosphere in the historic mountain town of Llanberis, complete with family activities including the ERYRI MINI kids' race.