The Race
| Next Race Date | 24 October 2026, the 42nd edition |
|---|---|
| Course type | Loop: start and finish both in Llanberis, encircling Yr Wyddfa via the Llanberis Pass and Beddgelert |
| Registration | Ballot. 2026 ballot entry is closed per the official site; ballot and entry method should be verified annually, since mechanism and dates can change year to year |
| Ballot Opens | Not confirmed for the 2027 edition; verify against the official site once announced |
| Total finishers | Not confirmed |
| Avg race-day temp | Not confirmed. Late October in Snowdonia should be planned for cold, wet, mountain-weather conditions rather than mild autumn UK-average assumptions |
| Cutoff time | Not confirmed |
| Free race-day transport | Not confirmed. Exact start, parking and bus/road-closure information should be taken from the official Race Day Info page when updated closer to the event |
| Course certification | Not confirmed |
Widely branded one of the UK’s toughest marathons, and it lives up to it
Marathon Eryri, the Snowdonia Marathon under its current official Welsh-language name, reached its 42nd edition in 2026, a classic road marathon encircling Yr Wyddfa through Llanberis and the Snowdonia mountain passes. The organiser’s own branding calls it one of the UK’s toughest marathons, and independent Reddit runner reports back this up in specific, credible detail: hills described as genuinely demoralising, a route through mountain passes where hill-specific training matters, and a route best approached with conservative early pacing rather than an assumption of PB conditions. What softens the physical demands is the crowd support, described by multiple runners as amazing despite the race’s remote, mountainous setting, and the exceptional destination value of the surrounding Eryri/Snowdonia National Park itself, from Yr Wyddfa to Caernarfon Castle. This is a race for runners chasing a genuinely demanding mountain marathon in spectacular scenery, not a fast finishing time, and one where hill-specific training before arrival matters more than for almost any other UK road marathon.
History
Marathon Eryri, known in English as the Snowdonia Marathon, reached its 42nd edition in 2026, a classic road marathon encircling Yr Wyddfa (Snowdon) through Llanberis and the Snowdonia mountain passes. The race is widely branded as one of the UK’s toughest marathons, a characterisation strongly backed up by consistent Reddit runner reports describing the route as spectacular, the hills as genuinely demoralising at points, and the crowd support as amazing. This is a distinct event from the Snowdonia Trail Marathon Eryri, a separate July trail race organised by Always Aim High Events covering 27 miles with 1,750 metres of ascent; the two must never be merged or conflated. No confirmed finisher count has been sourced for this race.
The course
Marathon Eryri runs as a classic road marathon encircling Yr Wyddfa, through Llanberis and the Snowdonia mountain passes. The course climbs out of Llanberis via the Llanberis Pass, continues to Beddgelert, climbs a second time to a high point widely referred to as Bwlch y Groes, roughly 1,200ft, before descending back to Llanberis. A real finisher’s device recording of the course confirms two major climbs: the first from around km 3 to km 7.5, rising from roughly 120m to 365m, and the second from around km 35 to km 39, rising from roughly 130m to 371m, with a low point of around 49m near Beddgelert at roughly km 21. This is genuinely not a fast or PB-oriented course: the race’s own “toughest marathon” branding is backed by strong, consistent runner-review evidence. One Reddit first-marathon report called the route spectacular, described the hills as demoralising, and praised the crowd support as amazing; a separate report described a striking, hilly route through mountain passes where hill-specific training genuinely matters. The clear editorial framing for this race is to pace conservatively and train specifically for sustained climbing and descending, rather than approach it like a flat road marathon.
Logistics Map
The map below shows the course: the loop out from Llanberis, around Yr Wyddfa via the Llanberis Pass and Beddgelert, and back to the finish at the same point. Tap the marker for details.
Departing the mountain’s gateway village into the Snowdonia passes.
Genuinely demanding climbing through the mountain passes, widely described by runners as the toughest section.
Continued challenging terrain, with strong crowd support helping runners through the hardest stretches.
Closing the loop around Yr Wyddfa at the same village the race began.
Pacers
Not confirmed. No pacer programme has been sourced for this race. Given the genuinely hilly, demanding profile, runners should plan conservative early pacing specifically to manage the climbing rather than banking time in the flatter sections.
What to wear
Late October in Snowdonia should be planned for cold, wet, genuinely mountain-weather conditions rather than mild UK-autumn averages. Given the exposed mountain-pass sections and the race’s own reputation as one of the UK’s toughest marathons, layers suited to changeable, cold conditions are a sensible baseline rather than an optional precaution. No specific mandatory kit list or headphone/bone-conduction rule has been confirmed for this race.
Entry
Entry operates via ballot; 2026 ballot entry is closed per the official site. Ballot and entry method should be verified annually against the live official Marathon Eryri site, since dates and mechanism can change year to year, and no 2027 ballot opening date has been confirmed. Specific entry pricing and refund policy have not been sourced.
Fast Runner / GFA Standards
Not confirmed. No Good for Age, elite or fast-runner entry pathway has been sourced for this race.
Race Weekend
Expo
Not confirmed. No expo information has been sourced for this race; many UK races of this scale use posted numbers or race-day collection instead. Check the official Marathon Eryri site closer to race day for current-year registration and collection details.
Race Morning
The race starts and finishes in Llanberis, Gwynedd. Exact start location, parking and bus or road-closure information should be taken from the official Race Day Info page once updated closer to the event. Llanberis itself has genuinely limited accommodation, and runners should book early rather than assume last-minute availability.
Nutrition on Course
Not confirmed. No confirmed aid-station locations have been sourced for this race; verify exact water and fuel-station locations from the current official race guide before travelling, given the course’s genuinely demanding mountain profile.
Spectating
Despite the race’s remote, mountainous setting, Reddit runner reports specifically describe amazing crowd support along the route, a genuine positive signal for spectator presence even in this demanding terrain. No official named spectator vantage points have been sourced; assume genuinely low spectator density away from Llanberis itself given the mountain-pass setting, though this is somewhat offset by the strong support reported by runners.
Itinerary: Base in Llanberis to see runners at the start and finish, the practical single spectating hub for this remote, mountainous course. No confirmed mid-course spectator route through the mountain passes has been sourced.
Post-Race Food
Llanberis, close to the finish, offers the practical post-race option for runners not travelling further afield, though its supply is genuinely limited given the village’s small size. No specific named restaurant has been sourced with confidence for this guide.
Where to Stay
Marathon Eryri’s start and finish are both in Llanberis, so there is no start-versus-finish trade-off for accommodation, only a decision about how much of Llanberis’s limited supply to compete for.
Llanberis
Offering the best start and finish convenience, is genuinely scarce on accommodation and should be booked as early as possible given both the race’s popularity and the village’s small size.
Caernarfon
A short distance away with its own castle and more accommodation supply, works well with some race-morning transport planning.
Bangor and Betws-y-Coed
Bangor, a larger town with rail links, offers a practical alternative for runners willing to arrange transport to Llanberis. Betws-y-Coed, a well-known Snowdonia base in its own right, can work for runners prioritising a scenic stay over race-morning simplicity, with transport planning required.
Recommended areas
The best start and finish convenience, though genuinely scarce; book as early as possible once entry is confirmed. No specific named property has been sourced with confidence.
More accommodation supply and its own castle, working well with some race-morning transport planning. No specific named property has been sourced with confidence.
A larger town with rail links, a practical alternative for runners willing to arrange transport to the start. No specific named property has been sourced with confidence.
Booking timeline
Book accommodation earlier than for a typical city race; Llanberis’s genuinely scarce supply means early booking matters more here than for most UK marathons. Caernarfon, Bangor and Betws-y-Coed all offer more capacity for runners willing to plan transport to the start. No specific race-weekend price premium has been sourced for accommodation around this event.
See & Do
These attractions sit at the start/finish itself, or a short journey into the surrounding Eryri/Snowdonia National Park.
Yr Wyddfa (Snowdon)
At the start/finish itself. The mountain the marathon’s own course encircles, with several ascent routes and the Snowdon Mountain Railway for those not wanting to walk up.
Llanberis Lake Railway
A gentle, low-effort narrow-gauge railway ride along Llyn Padarn, a good option for legs recovering from a genuinely hilly marathon.
Dinorwig Quarry and the National Slate Museum
Close to Llanberis. The former slate-quarrying landscape above the village, with a free museum covering the industry that shaped the region.
Caernarfon Castle
A short drive from Llanberis. One of Wales’s best-known medieval castles, a strong day-trip extension for runners with time to spare.
Beddgelert
A drive through Snowdonia from Llanberis, and passed directly by the marathon course. A well-known Snowdonia village with gentle riverside walking, a good low-effort option for a slower day after the race.
Read Before you Run
Feet in the Clouds
Richard Askwith
Askwith's account of British fell running culture gives runners genuine context for the mountain terrain and demanding hill tradition that Marathon Eryri's own course draws on, a fitting companion for a race widely branded as one of the UK's toughest marathons.
After the Race
Marathon Eryri runs in October. These itineraries stay close to Llanberis and Caernarfon, or extend further into North Wales, suited to runners recovering from a genuinely hilly mountain marathon.
Gentle, low-effort walking around Llanberis and the base of Yr Wyddfa, suited to legs recovering from a genuinely hilly marathon.
One of Wales's best-known medieval castles, an easy day-trip extension close to the race base.
A longer extension taking in Conwy and Llandudno alongside further North Wales castles.
Frequently asked questions
Should I stay near the start or the finish?
They are the same place. Marathon Eryri starts and finishes in Llanberis, so there is no start-versus-finish trade-off, only a decision about how much of Llanberis's limited accommodation to compete for.
How far in advance should I book a hotel?
Earlier than for a typical city race. Llanberis's accommodation supply is genuinely scarce, and this is a genuinely popular race, so book as soon as entry is confirmed.
Is there free transport to the start?
Not confirmed. Exact parking and bus/road-closure information should be taken from the official Race Day Info page once updated closer to the event.
What is the best area to stay?
Llanberis itself for the best start and finish convenience, or Caernarfon for more accommodation supply and its own castle if you're willing to plan race-morning transport.
When does the expo open?
Not confirmed. No expo information has been sourced; many UK races of this scale use posted numbers or race-day collection instead.
What is the weather typically like?
Not confirmed for a specific average. Late October in Snowdonia should be planned for cold, wet, genuinely mountain-weather conditions rather than mild UK-autumn averages.
How do I get from the airport?
Not confirmed. No specific airport transfer route has been sourced; this is a genuinely remote race location requiring careful travel planning.
Is there a bag drop?
Not confirmed. No bag-drop arrangement has been sourced for this race.
Should I bring a throwaway layer?
Yes. Given the exposed mountain-pass sections and cold, wet late-October conditions typical of Snowdonia, a discardable layer at the start is a sensible precaution.
How do I get back to my hotel after finishing?
Runners staying in Llanberis can walk back directly. Those staying in Caernarfon, Bangor or Betws-y-Coed should plan a car journey, since no dedicated race-day shuttle has been confirmed for this event.