Trail ultramarathon · United Kingdom
Expected 14–16 May 2027 · Llanberis, Eryri (Snowdonia)
UTS 100K: Expected Sat, 15 May 2027
A technical UK mountain ultra weekend in Eryri (Snowdonia), with rocky ridges, slate country, exposed climbs, and demanding weather windows.
2027 date is estimated
The organizer has not announced the next date yet. This estimate keeps planning useful without presenting it as official.
The mapped GPX is carried forward from 2026 until the new course is verified. Use it for course research, then re-check before race day.
Date sourceEntry · UTS 100K · 2027 edition
First come, first served: Mon 5 Oct 2026, 10:00 BST for UTMB Index holders; Wed 7 Oct 2026, 10:00 BST for everyone. Places can run out.
Subscribe to these entry dates (updates when the organizer's dates change and we recheck them) · Download .ics. Separate from any training calendar; remove it any time in your calendar app.
From the organizer's page, checked 1 Oct 2026. TrailSplits does not know whether you have a place; the organizer is the final word.
Eryri by UTMB is a trail ultramarathon expected around 14–16 May 2027 in Llanberis, Eryri (Snowdonia), United Kingdom. TrailSplits currently includes 4 mapped courses for this event, with course maps, elevation profiles, weather context, and pacing tools for the uploaded GPX data.
How to get a place: Direct purchase 'without pre-registration and lottery' for the May 2027 edition: UTMB Index holders from 5 October 2026, everyone from 7 October 2026, until 2 April 2027 or until full; no waiting list. Organizer's page, checked Thursday 1 October 2026.
TrailSplits is a free, independent route & pacing companion — not the official race. Visit the official Eryri by UTMB site →
Finishing UTS 100K earns 3 Running Stones (100K category) toward the UTMB World Series Finals lottery. How Running Stones work.
Racing more than once next year? Add UTS 100K to a season and see whether your races work together.
Inspect the official course track on a topographic map, through its elevation profile, or in 3D.
› running direction two lines: out and back on the same path kilometres
Selected distance
Vert-focused blueprint with route-finder links into the Planner.
Other distances
Prepare and return
Keep this course, its training plan, calendar and future course updates together in your private My Races page. Saving does not publish your workouts, pace or progress.
Race route lab
Open the official course in Planner, then choose a nearby start point to build a shorter loop that matches the course demand. This course averages about 50.9 m climb per km.
Expected Sat, 15 May 2027
Send to your watch
Get the official course as a clean GPX or a Garmin TCX course, with step-by-step instructions to load it onto a Garmin, COROS, Suunto, Wahoo, or Komoot — free, no account needed.
Compare your training
See how faithfully your rehearsal route matches the real race. The official course for UTS 100K loads as Route A — upload your training route to compare distance, elevation gain, estimated time, and how much of the course you actually cover.
Course analysis
See the UTS 100K course broken into its major climbs and descents in order — length, gain, average grade, and steepness — so you know where the crux is and how to pace and fuel it.
Race-week reminders
A free browser notification in the final week — the course crux, the weather window, and loading the GPX onto your watch. No app, no email, no account.
Eryri by UTMB 2027 races are expected to run 14–16 May 2027 in Llanberis, Eryri (Snowdonia); the UTS 100K is expected on Sat, 15 May 2027. Check the official race site for registration deadlines and final details.
4 distances (56–163 km). The longest course is 163 km with about 9,200 m of vertical gain — a demanding mountain course.
The UTS 100M course has a 48-hour cut-off, an average of 17.7 min/km to finish in time. TrailSplits' cut-off pacer shows the buffer at each aid station.
Yes. TrailSplits gives you the course map, an interactive elevation profile, a 3D flyover and a downloadable GPX for every mapped distance — free and with no sign-up.
Each distance has a free, course-specific 16-week training plan built around its distance, vertical gain and cut-offs, plus a pace and cut-off calculator.
No. TrailSplits is a free, independent route and pacing companion. For registration and official rules, visit https://eryri.utmb.world/.
Load the GPX directly into TrailSplits for surface analysis and terrain intel.