About Eryri by UTMB

Beautiful beyond belief. Savage beyond reason.

Eryri by UTMB is a mountain ultra-trail running event set in the heart of Eryri (Snowdonia) National Park in North Wales. Taking place from 14–16 May 2027, it brings together five races across a landscape of rugged peaks, technical mountain trails, rocky ridgelines and remote valleys.

This is a place that demands respect. The terrain is challenging, the weather can change quickly and every distance brings its own test. From the Eryri 25K to the 100M, runners will discover a landscape that is as unforgiving as it is extraordinary.

Part of the UTMB World Series, Eryri by UTMB offers an opportunity to experience mountain ultrarunning in one of the UK's most distinctive landscapes.

The 25K, 50K, 100K and 100M routes starting in Llanberis, and the 80K route starts at Caernarfon Castle.

Eryri 100M represents the ultimate grand-tour of the mountains of Snowdonia National Park, taking in the most notable peaks and trails of the area in the north.

Eryri 100K comprises the highlights of the mountainous areas of northern Snowdonia. With technical trails and epic views in abundance, it really is the pinnacle of Ultra-Trail® race routes in the UK!

Eryri 80K starting from the iconic Caernarfon Castle on Friday evening, this race takes you into the sunset from sea to mountain. A different challenge to the other races, setting off as the sun sets on an epic adventure. The perfect way to experience a night race, break past the 50K distance or bridge the gap to a multi-day longer distance event.

Eryri 50K follows similar trails to its bigger siblings and acts as the perfect stepping-stone into Alpine-scale mountain ultrarunning. For more experienced runners, it also represents an ideal Ultra-Trail® training race for longer events.

Eryri 25K offers runners of all abilities a taste of Eryri, with 1 Running Stone on offer for all finishers, allowing entry to the UTMB® Mont-Blanc ballot.

To learn more, see the List of Races.

Each distance features 1,300 / 3,300 / 6,500 / 9,600m+ elevation gain respectively, on predominantly technical mountain trails. This makes Eryri one of, if not the toughest Ultra-Trail® events in the world. Eryri isn’t just challenging for the sake of it though: exploring Eryri's (Snowdonia’s) most scenic valleys, rugged peaks and epic landscapes, our race routes are truly the most beautiful in the UK!

Previously Ultra-Trail Snowdonia, Eryri by UTMB was the brainchild of British runner Michael Jones. While training for UTMB® in 2015, he wondered why there was no similarly mountainous ultra in the UK... Now approaching it's seventh edition and with four distances on offer, don't miss your opportunity to be a part of this unique, spectacular and EPIC trail running event!

This is Eryri by UTMB, the UK’s first Alpine-scale ultra: Beautiful beyond belief. Savage beyond reason.

Eryri by UTMB began with a simple idea. In 2015, British runner Michael Jones was training for UTMB in the Alps and wondered why the UK didn't have an ultra-trail race that offered a similarly demanding mountain experience.

That idea became Ultra-Trail Snowdonia by UTMB, first held in 2018. The inaugural race was a tough introduction to the mountains, setting the tone for an event built around technical terrain, unpredictable conditions and the uncompromising character of Eryri.

From those early beginnings, the event grew into one of the UK's best-known mountain ultra-trail races, attracting runners from across the world to take on its challenging routes. Its growth has brought international attention to the trails and landscape around Llanberis, while its identity has remained rooted in the mountains that inspired it.

In 2027, the event enters a new chapter as Eryri by UTMB. The name reflects the Welsh identity of the place that has shaped the race from the beginning, while carrying its story forward as part of the UTMB World Series.

The name has changed, but the mountains, the challenge and the spirit of the race remain.

Eryri by UTMB is part of the UTMB World Series. Completing a race earns runners Running Stones, which give them entries into the lottery for the UTMB World Series Finals at HOKA UTMB Mont-Blanc in Chamonix. The number of Running Stones earned depends on the race category: 1 for 20K, 2 for 50K, 3 for 100K and 4 for 100M.

Running Stones accumulate over time, and runners need at least one earned within the previous two years to enter the Finals lottery. Each additional Running Stone gives them another chance of being selected.

For runners looking to take their trail-running journey further, Eryri by UTMB offers the opportunity to challenge themselves in the mountains of North Wales while working towards a place on one of trail running's biggest stages.