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A small boat on a lake at Llanberis in low sun, with the hills mirrored in the water
Josh Willett / Unsplash

Eryri by UTMB (Ultra-Trail Snowdonia) course maps and aid stations

Five races in the mountains of North Wales, from a 25K over Yr Wyddfa to a 100 miler with 9,200 m of climbing.

May 14 to 16, 2027 Llanberis, Gwynedd, Wales

Eryri by UTMB is the race that was called Ultra-Trail Snowdonia until 2026. The park went back to its Welsh name, Eryri, in 2022, and from 2027 the race uses it too. It's a UTMB World Series event, and the 2026 edition, its eighth, had over 2,800 runners of more than 60 nationalities.

Four of the five courses start and finish in Llanberis, at the foot of Yr Wyddfa (Snowdon). The 80K starts on the coast in Caernarfon and runs back to Llanberis through the night. The 100M is a lap of northern Eryri through Capel Curig, Blaenau Ffestiniog and Beddgelert.

Signal may be patchy in parts of the park, the Eryri National Park Authority says, and the organizer wants 100M runners able to navigate with map and compass in the dark if needed. Save the course to your phone before the start. The map then works offline, and GPS puts you on it with no signal at all.

This is an unofficial guide: Goat Maps isn't affiliated with Eryri by UTMB. Check the official site before you enter or race.

Eryri course map

Every course's aid stations on the Goat Maps topo map. Each course has a map of its own further down.

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Save it in Goat Maps for a recce or race day. GPS shows where you are even without a signal.

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Eryri courses

CourseDistanceClimbingStartTime limit
100M163.9 km (101.8 mi)9,200 m (30,184 ft)Fri, May 14, 2:00 PM48 h
100K107.9 km (67 mi)5,800 m (19,029 ft)Sat, May 15, 5:30 AM32 h 30 min
80K78.6 km (48.8 mi)2,500 m (8,202 ft)Fri, May 14, 8:00 PM16 h
50K57.6 km (35.8 mi)3,400 m (11,155 ft)Sat, May 15, 8:30 AM14 h
25K24.7 km (15.3 mi)1,300 m (4,265 ft)Sun, May 16, 8:00 AM5 h 30 min

Eryri 100M

Friday 2 PM from Llanberis, 48 hours, a lap of northern Eryri over most of its big hills.

Distance
163.9 km (101.8 mi)
Climbing
9,200 m (30,184 ft)
Start
Fri, May 14, 2:00 PM
Time limit
48 h

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The 100M climbs straight to Bwlch Glas below the summit of Yr Wyddfa, drops to Pen-y-Pass (water only) and goes over Glyder Fawr to the Ogwen Valley. From there it crosses Carnedd Llewelyn to Llyn Eigiau, then Moel Siabod, and heads south through Dolwyddelan and Blaenau Ffestiniog to Moelwyn Mawr, Croesor and Cnicht. Later come Moel Hebog, the summit of Yr Wyddfa from Rhyd Ddu, and Mynydd Mawr. Moel Eilio is the last climb.

Your drop bag is at Croesor, 84.6 km in. Crews can meet you at Dolwyddelan, Blaenau Ffestiniog, Beddgelert and Bron-y-Fedw Uchaf. The longest gap is the last one: 16.4 km from Betws Garmon over Moel Eilio to the finish. The cutoffs are the race page's, and if they change, the organizer texts runners.

aid stations

kmWhereCutoff
0Llanberis (start and finish)
11.9Pen-y-Pass (water) Fri 5:30 PM
21.9Ogwen Valley Fri 8:00 PM
37.2Llyn Eigiau Sat 12:30 AM
49.5Capel Curig Sat 3:00 AM
59.8Dolwyddelan CrewSat 6:00 AM
72.3Blaenau Ffestiniog CrewSat 9:30 AM
84.6Croesor Drop bagSat 1:00 PM
98.2Gwastadanas Farm Sat 4:45 PM
112.3Beddgelert CrewSat 8:30 PM
126.7Rhyd Ddu Sun 2:00 AM
139.2Bron-y-Fedw Uchaf CrewSun 6:45 AM
147.5Betws Garmon Sun 9:45 AM
163.9Llanberis (start and finish) Sun 2:00 PM
Two lakes in a green cwm far below, seen from high on Yr Wyddfa under heavy cloud
Josh Kirk / Unsplash

Eryri 100K

Saturday 5:30 AM from Llanberis, 32 hours 30 minutes, on a longer course for 2027.

Distance
107.9 km (67 mi)
Climbing
5,800 m (19,029 ft)
Start
Sat, May 15, 5:30 AM
Time limit
32 h 30 min

Take this course offline

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The 2027 course is 108 km with 5,800 m of climbing, up from 106 km and 5,400 m in 2026; the organizer's file for it is called the 2027 100K Recce. It goes over Bwlch Glas to Gwastadanas Farm (water only the first time), then Moel Siabod, Dolwyddelan, Blaenau Ffestiniog, Moelwyn Mawr, Croesor and Cnicht. It comes back to Gwastadanas, where your drop bag is, then climbs over Yr Wyddfa.

Crews can meet you at Dolwyddelan, Blaenau Ffestiniog and Bron-y-Fedw Uchaf. The longest gaps are 16.8 km from Gwastadanas over the summit to Bron-y-Fedw Uchaf and 16.3 km from Betws Garmon over Moel Eilio to the finish.

aid stations

kmWhereCutoff
0Llanberis (start and finish)
14.1Gwastadanas Farm Sat 10:30 AM
28.2Dolwyddelan CrewSat 2:30 PM
40.6Blaenau Ffestiniog CrewSat 6:30 PM
52.8Croesor Sat 10:00 PM
66.5Gwastadanas Farm Drop bagSun 2:00 AM
83.3Bron-y-Fedw Uchaf CrewSun 6:30 AM
91.6Betws Garmon Sun 11:00 AM
107.9Llanberis (start and finish) Sun 2:00 PM
A rocky path climbing a grassy cwm toward the peak of Yr Wyddfa, with a small lake below
Craig Davis / Unsplash

Eryri 80K

Friday 8 PM from Caernarfon, 16 hours, from the sea into the mountains at night.

Distance
78.6 km (48.8 mi)
Climbing
2,500 m (8,202 ft)
Start
Fri, May 14, 8:00 PM
Time limit
16 h

Take this course offline

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A free shuttle leaves Llanberis for the start between 6:30 and 7 PM, no booking needed. You start by Caernarfon Castle at sea level, and the first part is fast and runnable. After the water stop at Y Fron and the aid station on the Llanberis Path, you climb to Bwlch Glas, just under the summit of Yr Wyddfa, at 37 km. Then it's down to Gwastadanas, round through Beddgelert and Rhyd Ddu, and a fast descent to Llanberis.

Beddgelert is the only crew point. Finishers get 3 Running Stones, but the 80K doesn't give its top three a place at the UTMB World Series Finals.

aid stations

kmWhereCutoff
0Caernarfon (80K start)
16.7Y Fron (water) Fri 11:00 PM
31.3Llanberis Path (80K) Sat 2:00 AM
45Gwastadanas Farm Sat 5:00 AM
59.1Beddgelert CrewSat 8:00 AM
67.5Rhyd Ddu Sat 10:00 AM
78.6Llanberis (start and finish) Sat 12:00 PM

Eryri 50K

Saturday from 8:30 AM in Llanberis, 14 hours, up to Bwlch Glas and later over the summit of Yr Wyddfa.

Distance
57.6 km (35.8 mi)
Climbing
3,400 m (11,155 ft)
Start
Sat, May 15, 8:30 AM
Time limit
14 h

Take this course offline

Download its map in Goat Maps and you can find the next aid station without a signal.

Open in web map

The 50K starts in three waves, at 8:30, 8:45 and 9:00, and the course closes at 11 PM. It climbs to Bwlch Glas and drops to Gwastadanas Farm, then goes back up over the summit of Yr Wyddfa and down to Bron-y-Fedw Uchaf. That's 17.6 km between aid stations, the longest gap on the 50K. Mynydd Mawr and Moel Eilio come after.

Crews can't meet you out on the course. Expect scrambling and narrow ridges.

aid stations

kmWhereCutoff
0Llanberis (start and finish)
15.3Gwastadanas Farm Sat 12:45 PM
32.9Bron-y-Fedw Uchaf Sat 4:45 PM
41Betws Garmon Sat 7:00 PM
57.6Llanberis (start and finish) Sat 11:00 PM

Eryri 25K

Sunday morning from Llanberis, 5 hours 30 minutes, with a full ascent of Yr Wyddfa.

Distance
24.7 km (15.3 mi)
Climbing
1,300 m (4,265 ft)
Start
Sun, May 16, 8:00 AM
Time limit
5 h 30 min

Take this course offline

Download its map in Goat Maps and you can find the next aid station without a signal.

Open in web map

The 25K goes off in three waves, at 8:00, 8:15 and 8:30, and the course closes at 2 PM. It takes in the whole climb of Yr Wyddfa, to 1,085 m, and has one aid station, at Tan yr Wyddfa, 13.7 km in. It's open to anyone 17 or older with no experience required, and finishers get a Running Stone.

The Snowdon Mountain Railway track running down a stony ridge, with hills and a lake far below
Yeka.UK / Unsplash

Registration

Entry for 2027 opened at 10 AM on 5 October 2026, for UTMB Index holders only for the first 48 hours and for everyone from 7 October. It closes at 23:59 on 2 April 2027, or sooner if a distance fills. There's no waiting list.

The 100M needs a UTMB Index in the 100K or 100M category, and the organizer recommends 380 or more to make the cutoffs. The other races need no Index. You have to be 20 on race day for the ultras and 17 for the 25K. The organizer also lists the training it expects for each distance: for the 100M, a long mountain run with scrambling, and enough skill to navigate with map and compass in the dark.

Getting to Llanberis

The nearest station is Bangor, with direct trains from Chester, Birmingham and Cardiff. Over race weekend a shuttle runs from Bangor station to the Ultra-Trail Village in Llanberis for £5 plus a booking fee. Otherwise the S2 bus runs twice an hour, or a taxi takes about 30 minutes and costs about £30. The closest big airport is Manchester, about two hours' drive away.

If you drive, use the event's Park & Ride north of Llanberis, off the A4086. A pass costs £45 for three days, £30 for two or £20 for one, plus an 8% fee, and you book it through your MyUTMB registration. Shuttles run from the car park to the village.

Crewing

A stone bridge over the river in Beddgelert, with slate houses and a wooded hillside
Martina Jorden / Unsplash

Crews can only meet runners at a few aid stations, because many are remote with little parking: Dolwyddelan, Blaenau Ffestiniog, Beddgelert and Bron-y-Fedw Uchaf on the 100M, three of those on the 100K, and Beddgelert on the 80K. One person per runner, inside a zone from 500 m before the aid station to 500 m after it.

There are no pacers. Running with anyone outside those zones earns a time penalty. The organizer strongly recommends a crew for the long races, and someone to drive you home afterward.

Weather and kit

At Capel Curig, an aid station on the 100M, the Met Office's May average is a high of 14.4°C and a low of 6.7°C, with 142 mm of rain over about 14 days. The park authority warns that the weather in the uplands can change within hours and that the summits are colder.

You carry everything on the mandatory kit checklist the whole way, and it's spot-checked at bib collection, at the start and at aid stations. Keep your phone on: switching it off or to airplane mode costs 15 minutes. If you use poles, you start with them and carry them to the finish.

Eryri aid stations and GPS coordinates

For crews and spectators: each place on the map in decimal degrees, latitude first. Paste them into any map app or add them as waypoints in Goat Maps.

  • Llanberis (start and finish)

    105 m (344 ft)

    53.11824, -4.11858

  • Caernarfon (80K start)

    6 m (20 ft)

    53.13886, -4.27559

  • Pen-y-Pass (water)

    372 m (1,220 ft)

    53.08048, -4.02247

  • Ogwen Valley

    305 m (1,001 ft)

    53.12528, -3.99062

  • Llyn Eigiau

    373 m (1,224 ft)

    53.16613, -3.91070

  • Capel Curig

    192 m (630 ft)

    53.10014, -3.91417

  • Dolwyddelan

    143 m (469 ft)

    53.05194, -3.88457

  • Blaenau Ffestiniog

    223 m (732 ft)

    52.99415, -3.93276

  • Croesor

    164 m (538 ft)

    52.98239, -4.03741

  • Gwastadanas Farm

    89 m (292 ft)

    53.06277, -4.00751

  • Beddgelert

    46 m (151 ft)

    53.01220, -4.10386

  • Rhyd Ddu

    186 m (610 ft)

    53.05214, -4.13554

  • Tan yr Wyddfa (25K)

    189 m (620 ft)

    53.05244, -4.13487

  • Bron-y-Fedw Uchaf

    152 m (499 ft)

    53.06708, -4.13421

  • Betws Garmon

    128 m (420 ft)

    53.09269, -4.18958

  • Y Fron (water)

    282 m (925 ft)

    53.06959, -4.22835

  • Llanberis Path (80K)

    206 m (676 ft)

    53.11043, -4.12161

  • Yr Wyddfa (Snowdon) summit

    1,085 m (3,560 ft)

    53.06849, -4.07623

Eryri FAQ

When is Eryri by UTMB 2027?

14 to 16 May 2027. The 100M starts at 2 PM on Friday and the 80K at 8 PM that evening; the 100K and 50K start on Saturday morning and the 25K on Sunday morning.

Is Eryri by UTMB the same race as Ultra-Trail Snowdonia?

Yes. Ultra-Trail Snowdonia became Eryri by UTMB for 2027, following the national park, which took back its Welsh name in 2022. The races are the same, still based in Llanberis.

Is Eryri a Western States qualifier?

Yes, for the 2028 Western States lottery, under its old name Ultra Trail Snowdonia: the 100M in under 48 hours or the 100K in under 28 hours. The 100K's own limit is 32 hours 30 minutes, so finishing isn't always enough.

Do I need a UTMB Index to enter?

Only for the 100M, which needs an Index in the 100K or 100M category. The organizer recommends 380 or more.

Can I have a pacer?

No. Being accompanied is only allowed in the zones around the aid stations, and a single crew member can help you there.

Is there phone signal on the course?

Not everywhere: the park authority says signal can be patchy. Your phone has to stay on during the race, so carry the course map offline and a way to charge.

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Updated . An unofficial guide, from the organizer's published information. Coordinates from the organizer's course and OpenStreetMap contributors. Photos from Unsplash. Organize a race? We help with course files.