About This Race
The 163K stands as the flagship distance at Ultra-Trail Snowdonia by UTMB, a full circumnavigation of the Snowdonia massif that tests runners across two days and nights of mountain travel. Starting and finishing in Llanberis, the route covers 163 kilometers through North Wales' most remote and demanding terrain, passing through multiple mountain ranges and valleys where navigation skills and self-sufficiency prove as important as fitness. With cutoff times extending beyond 30 hours, this race attracts experienced ultra-runners ready to engage with genuine mountain wilderness rather than simply log miles. As part of the UTMB World Series, the 163K holds significance beyond its borders, offering qualifying points for runners targeting entries to the Mont-Blanc circuit. The technical nature of Welsh mountain paths—slate, scree, and exposed rock—demands attention through every kilometer, even as exhaustion mounts. This is not a race to run on autopilot. The May date brings unpredictable Welsh weather into play. Runners should prepare for everything from sun exposure on open ridges to driving rain and potentially snow on higher summits. Night sections require solid navigation skills, as the route travels through areas with minimal ambient light and limited human presence. The 163K serves those seeking honest mountain challenge rather than curated spectacle.
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.
Location
Practical Info
May in Snowdonia brings highly variable conditions—mild valley temperatures but summit weather ranging from clear to severe, with rain, wind, and occasional snow possible on exposed sections. Runners should prepare for full mountain weather protection.
MAN - Manchester Airport
Llanberis offers limited accommodation that books early for race weekend. Nearby towns including Caernarfon, Bangor, and Betws-y-Coed provide additional options within reasonable driving distance of the start/finish area.