A trail runner on a grassy ridge above a sea of clouds

Snowdonia Trail Marathon Eryri

The Snowdonia Trail Marathon Eryri is based in Llanberis, a mountain village in the Eryri range of north Wales.

Prepare for Snowdonia Trail Marathon Eryri

A plan built from your answers and your race date.

trail training plan

The Snowdonia Trail Marathon Eryri is based in Llanberis, a mountain village in the Eryri range of north Wales. The terrain is classic Welsh mountain trail: rocky paths, grassy slopes, wind-exposed sections and weather that can change quickly even in the middle of July.

8km and an ultra. The 10K is run on 10 July, with the half, marathon and ultra following on 11 July. The event is organised by Always Aim High Events and is a separate race from Eryri by UTMB, which is also based in the region, so check carefully which event you are entering.

The formats

3 formats on the program.

Format	Distance
10K	6.1 mi
Half Marathon	13.2 mi
Marathon	27.2 mi

Organizer information, checked on September 21, 2026 · alwaysaimhighevents.com

When to start

A build for this distance usually runs 12 to 24 weeks. Counted back from race day, that puts the start somewhere between January 18, 2027 and April 12, 2027.

These ranges are working conventions, not a research finding — no trial has compared plan lengths against each other. What matters more is that the plan was built for the weeks you actually have, rather than shrunk down from a longer one.

How to choose your start date

When to start

January 18, 2027

→ April 12, 2027

Worth reading before you enter

Races and distances Trail distances: what changes off the road Distance stops being the useful number. What decides a trail race is how long you are out, how much you climb, and how much the descents have wrecked your legs by the end. Read Training Eating and drinking: what’s proven, what isn’t This is where confident advice most often runs ahead of the evidence. Some of it is well tested. Some is opinion wearing a number. And one common habit can kill you. Read Races and distances When to start preparing your race Most plans fail before the first session, because the block started too late and everything had to be squeezed. Counting back from the date is the dullest and most useful thing you will do. Read

Questions

What is the date of Snowdonia Trail Marathon Eryri in 2027?

Snowdonia Trail Marathon Eryri is run on Saturday, July 10, 2027 in Llanberis. Date published by the organizer, checked on September 21, 2026.

What distances does the Snowdonia Trail Marathon Eryri offer?

8km marathon and an ultra. Note the marathon is longer than the standard road distance by more than a kilometre.

Is the Snowdonia Trail Marathon the same as Eryri by UTMB?

No. The Snowdonia Trail Marathon Eryri is run by Always Aim High Events and is a separate event from Eryri by UTMB. Check the organiser name and official website before you enter.

Other races

This list keeps growing; it draws no line. A race that is missing is prepared for in exactly the same way.

Edale → Kirk Yetholm (Pennine Way) · United KingdomUltra Montane Winter Spine Jan 9 The full race covers 431km, with shorter Challenger and Sprint formats alongside it. Cornish coast · United KingdomUltra Arc of Attrition by UTMB Jan 22 The Arc of Attrition by UTMB is a winter ultra run along the Cornwall coast path in England. 1 km to 173 Bath · United KingdomHalf marathon GetPRO Bath Half Marathon Mar 14 1 km half marathon run through the streets of central Bath, England. Your race is not here? Tell us about your race You can prepare for it all the same. Any race, anywhere, and even a goal without a race.

Your race is on the calendar. Your plan should be too.

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