Ultra Trail UK

Self-navigated running, UK

Eryri by UTMB

Written by Catriona Adams. Published 10 August 2026

Eryri by UTMB — formerly Ultra-Trail Snowdonia — is a fully organised ultra-trail race through Eryri (Snowdonia National Park) in North Wales, offering five distances from 22km to 163km. Running since at least 2018, it's one of two UK races carrying the UTMB World Series brand, alongside Arc of Attrition by UTMB in Cornwall.

Key points

  • Five distances: 25K, 50K, 80K, 100K and 100 Miles, all in Eryri (Snowdonia National Park), North Wales.
  • Formerly Ultra-Trail Snowdonia, renamed Eryri by UTMB in 2027; running since at least 2018.
  • One of two UK races on the UTMB World Series — the other is Arc of Attrition by UTMB in Cornwall.
  • Fully organised: marked course, aid stations, entry list — the opposite of a self-navigated Round.

The distances

LocationEryri (Snowdonia National Park), North Wales
25K22 km, 1,100 m+
50K56 km, 3,400 m+
80K78 km, 2,500 m+
100K106 km, 5,400 m+
100 Miles163 km, 9,200 m+
2026 edition dates15–17 May 2026
Running sinceAt least 2018 (2026 is its eighth edition)
SeriesUTMB World Series

How it fits the wider UTMB circuit

Eryri by UTMB carries the same UTMB World Series branding as the flagship UTMB race in Chamonix and its circuit of qualifying and Major events across France, Spain and elsewhere. Finishers at Eryri earn Running Stones — the UTMB World Series' qualification currency toward the HOKA UTMB Mont-Blanc lottery and Finals — with the exact count depending on distance. For the broader circuit beyond the UK, including the France/Spain races, see utmb.es.

Organised race, not a Round

Eryri crosses some of the same Snowdonia peaks as the Paddy Buckley Round — but where the Round has no marked course, no aid stations and no fixed date, Eryri supplies all three: a flagged route, checkpoints, and a start list on set dates each May. Same mountains, opposite discipline.

FAQ

Frequently asked questions

An organised ultra-trail race in Snowdonia National Park, Wales, offering five distances from 22km to 163km. It was previously called Ultra-Trail Snowdonia and was renamed Eryri by UTMB in 2027.

No — Arc of Attrition by UTMB in Cornwall joined the series for the 2025 season. Eryri and Arc of Attrition are the two UK races currently carrying the UTMB brand.

163 km (about 101 miles) with roughly 9,200m of elevation gain — the longest of the five distances offered.

Eryri by UTMB is a marked, organised race with aid stations, cut-offs and an entry list on set dates in May. The Paddy Buckley Round covers similar mountains with none of that — no marked course, no organiser, attempted any day a runner chooses.

It places the race in the same global circuit as UTMB itself in Chamonix — runners can earn qualification points ('Running Stones') toward the UTMB World Series Finals by racing here, under the same ranking system used across the series' events worldwide.

Sources for this page

Related

UK Ultra-Trail RacesPaddy Buckley RoundThe self-navigated alternative, same mountains