Trail running course through technical terrain in Wales, GB
Ultra-Trail Snowdonia by UTMB

Ultra-Trail Snowdonia by UTMB 25K

25K·1,400m gain·Llanberis, United Kingdom
mountaintechnicaltrailqualifier

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Distance25K
Gain1,400m
Date15 May 2026
Difficulty2/5

About This Race

The 25K serves as the perfect introduction to Snowdonia's demanding terrain, offering runners a substantial mountain challenge without the ultra-distance commitment of the longer races. This distance strikes an ideal balance for those seeking to experience the technical rocky trails and elevation changes that define the event, while maintaining a pace that allows for appreciation of the dramatic Welsh landscape. Strong trail runners new to mountain ultras will find this distance provides serious preparation for future UTMB World Series events, while experienced mountain runners can use it as a intense training run or recovery race between bigger objectives.

The 25-kilometer introduction to Ultra-Trail Snowdonia features 1,400 meters of elevation gain. This Running Stones 1 category race offers newcomers a taste of Welsh mountain running without ultra-distance commitment.

Location

Practical Info

Weather

Variable mountain conditions typical of North Wales in May, with potential for rain, wind, and temperature changes with elevation

Nearest Airport

MAN - Manchester Airport

Accommodation

Llanberis offers various accommodation options from B&Bs to hotels, with additional lodging available in nearby Snowdonia villages

Best For

experienced trail runnersultra runnersmountain runners

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.

Other Distances at This Event

56K

The route ventures into the heart of Eryri National Park, weaving through terrain that has tested mountain runners for generations. Expect sustained technical sections where route-finding instincts and scrambling comfort pay dividends. The Welsh mountains may lack the raw altitude of Alpine peaks, but compensate with unrelenting terrain underfoot and weather that shifts without warning.

78K

The route departs Llanberis and moves through the Glyderau range before continuing across the rugged landscape that defines this corner of North Wales. Runners encounter sustained climbs on rocky trails, exposed sections where weather can change rapidly, and technical descents that demand concentration late in the race. The course includes multiple mountain passes and ridgeline sections, with terrain ranging from well-worn footpaths to loose scree and boulderfields that require picking careful lines at pace.

100K

The route departs Llanberis and ventures deep into Snowdonia's core mountain ranges, utilizing a mix of rocky mountain paths, ridge traverses, and technical singletrack. Runners encounter the full character of Welsh mountain terrain: steep rocky climbs, technical descents requiring careful foot placement, and exposed sections where weather exposure becomes a factor in race strategy. The course includes significant night running, with most finishers completing the distance across two nightfall periods. Navigation demands increase after dark, making headlamp skills and the ability to read terrain in limited visibility critical to forward progress. Aid stations provide strategic resupply points, but self-sufficiency between stations remains important given the remote nature of much of the route.

163K

The route travels clockwise from Llanberis, moving through the Glyderau range before dropping into the Ogwen Valley. From there, runners head south through the Carneddau mountains and into more remote terrain around the Moelwynion range. The return leg passes through the dramatic landscapes near Beddgelert before the final push back to Llanberis through the shadow of Snowdon itself. Aid stations are spaced to accommodate mountain logistics rather than runner convenience, with some sections requiring sustained self-sufficiency between support points.