Sun 13 Jul 2025 Caernarfon, Gwynedd, UK

XTERRA Snowdonia Trail Marathon Eryri

The most epic trail marathon in Wales! Iconic and spectacular trails, circumnavigating then climbing the slopes of Wales' highest peak - Yr Wyddfa (Snowdon).

  • Sun 13 Jul 2025
Llanberis, Caernarfon




Age 18 & over

  • 27.3 miles trail running + 1685 m ascent


Entering the XTERRA Snowdonia Trail Marathon is your ticket to compete in one of the UK's most challenging trail races.


The incredible routes explore the trails, gorgeous panoramic views and tough climbs that make Snowdonia National Park so popular with outdoor enthusiasts.

Visiting Rhyd Ddu, Beddgelert, Nant Gwynant, Pen y Pass, and Snowdon, there surely can't be a more striking trail marathon route in the UK!


  • One of the UK's most challenging trail races

    The ultra and marathon are UTMB-indexed.

  • XTERRA Trail Run World Series

    The marathon and half marathon are part of the World Series.

  • Spectacular scenery

    Unbeatable views across Eryri (Snowdonia).

  • Lively event village

    Music, commentary, shopping, food, kit demos and toilets.

  • Family friendly vibes

    Family finishes and plenty to see and do.

  • On course support

    Friendly marshals, signage, energy stations and support vehicles.

  • Unique finisher mementos

    Beautifully designed to reflect our event locations and local history.

  • Professional timing

    Chip timing, live tracker and online results.

World Series

The XTERRA Trail Run World Series connects the entire trail running community through a global rankings system, regional championships, and for those who qualify - the XTERRA Trail Run World Championship.

This event is part of XTERRA Snowdonia Trail Marathon Eryri Events.

Event video

  • All fitness levels
  • Event expo
  • Event village
  • Families
  • Free venue entry
  • Newcomers
  • Spectators
  • Traders at event


A list of compulsory and advisable kit is readily available.

Walking poles

You are permitted to carry and use walking poles if you wish to.


The event village is family-friendly and is at a location with lots on offer for families. There'll be a great atmosphere for spectators who can track the person they are supporting using an app so they don't miss them at key points.

  • Bag storage
  • Cafe
  • Mountains
  • Paid parking
  • Toilets

Event HQ


Llanberis, North Wales has superb transport links and is incredibly easy to find.


Registration is located on the event field in Llanberis situated next to the Community Centre - LL55 4UR.



Parking information is included in your Final Instructions email. Please be considerate to local residents when parking and use official event parking or pay and display car parks.

By car

There’s quick, straightforward access from the North West along the M56 and A55. Motorway links with the Midlands are good too, and the same roads – the M6, M5 and M1 – also bring Snowdonia within easy reach of the South of England

By rail

Direct services (including direct trains from London to Bangor) take you to the popular North Wales coastal destinations from most parts of Britain.

The closest station to Llanberis is Bangor, which is just under 10 miles away. A taxi from here will cost approximately £25. The Sherpa S2 bus will take you from the station and cost between £3-£5. It is possible to cycle.

By sea

Irish Ferries and Stena Line operate regular and high-speed services to Holyhead from Dublin.

By air

Transfers from the international gateways of Manchester, Liverpool and Birmingham take less than two hours.


Llanberis and the surrounding areas offer a wide range of hotels, bed and breakfast, campsites and hostels.

The Royal Victoria Hotel is recommended.

  • First aid
  • Food stations
  • Marshals
  • Mass start
  • Mountainous
  • No headphones
  • Out and back
  • Sweeper
  • Water stations


The incredible route explores the trails, gorgeous panoramic views and tough climbs that make Snowdonia National Park such a popular destination for outdoor enthusiasts.

Probably the biggest trail marathon in the UK, the Snowdonia Trail Marathon is a challenge in every sense of the word. Ascending 1,685 metres over 27 miles of iconic and spectacular trails, this epic race will circumnavigate and eventually climb Wales' highest peak - Yr Wyddfa (Snowdon). Visiting Rhyd Ddu, Beddgelert, Nant Gwynant, Pen y Pass and Snowdon (via the PyG Track to the Finger Stone) to then descend to the finish line via the Llanberis Path. There surely can't be a more striking trail marathon route in the UK!


Cut off times

There will be staged cut-offs across the race to ensure the safety and well-being of volunteers and competitors.

  • 11:20 | Mile 11.5 - Cut off at Beddgelert (average 4mph)
  • 14:00 | Mile 19.6 - Cut off at Pen y Pass (average 2.3mph)
  • 18:00 | Mile 27.4 - Finish line cut off (average 1.95mph)

Feed stations

There are 5 aid stations on the Marathon route, plus an emergency water station.

Water and High 5 energy drink and gels will be available at 2, 6, 11, 15 and 19 miles. At 11 miles (Beddgelert) and 19 miles (Pen y Pass), there will also be fruit, crisps and sweets. There will be an emergency water station at mile 23 (Clogwyn Station). Due to the difficulty of supplying water containers high on Yr Wyddfa (Snowdon), there will be limited supply here. Please ensure that you have filled your water bottles at the Pen y Pass aid station, and only take water at this station if absolutely necessary. the organisers are unable to re-fill water containers at this point.


The use of bone conduction headphones is permitted. Use of any other headphones is prohibited. This ruling is at the Race Directors' discretion in line with UKA rules due to runners needing to pass on single-track trails.

  • Plastic bottle free
  • Plastic-free event
  • Public transport links
  • Recycling
  • Reusable cups
  • Sustainability policy

As a local Welsh company the organiser's goal is to showcase the beautiful natural environment without causing harm. Event since their first race in 2011, they have avoided plastic bottles, offered locally-sourced Welsh slate finisher mementoes and have lead on sustainability in events.

  • Chip timing
  • Eco medal
  • Event app


There will be a prize-giving ceremony after the races. Prizes are not sent out after the event, so make sure you attend the ceremony and receive your big Welsh cheer!

Prize Categories for the Snowdonia Trail Marathon are (for both men and women).

  • Overall: Top 3*
  • V40: Top 3
  • V50: 1st runner
  • V60: 1st runner
  • V70: 1st runner

* If any runner places in Overall and Vet then a drop down system will occur.

  • Age 18 & over
  • Entries not yet open
  • Enter online
  • Series discount

Team Duo entries

The TEAM DUO CATEGORY provides an athlete the opportunity to share their running passion with a partner. Pairs of two will sign up and run together for the full trail distance. The DUO must stay within 15 seconds of each other during the full course, including the segment challenges.

Penalties will be added for DUOs not staying within the allotted distance, and time will be recorded for both partners based on the second runner who passes the segment and final finish lines.


If you opted for a postal entry there is no need to register in person before the event. Your Final Instructions will be printed on the back of your bib, and they will also be available on the website 10 days prior to the race.

If your bib is not being posted you will need to collect it from registration. Registration will take place on Saturday afternoon and before the race on Sunday morning. Specific times will be confirmed in your Final Instructions.

If you are looking for a challenge, the Snowdonia Trail Race is up there with the toughest in the U.K. A punishing and beautiful experience in equal measure, ensure this one is on your bucket list. Luke Royle (2019) RaceCheck

Absolutely AMAZING day - so well signposted, not the slightest chance of getting lost and wonderful camaraderie amongst all runners. I met some really wonderful people at various points on the course and it really keeps you going strong!!! Anonymous post-event feedback 2023

Loved running the marathon - many thanks for what was the best organised trail event I’ve done. The Marshalls were brilliant.  Post event feedback 2023



My first trail marathon and what can I say but 'WOW’. Adam Gurney, Racecheck

Race village, route marking, feed stations, marshals, views and sense of achievement at the very highest standard. Do it! Matt Hall (2022) RaceCheck

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