Marathon Eryri takes place on Sat, Oct 24, 2026 in Llanberis, United Kingdom. The main route is 42.2 km.
- Date
- Sat, Oct 24, 2026
- Start
- Llanberis 🇬🇧
- Distance
- 42.2 km
- Climbing
- 823 m
- Level
- Open to all
Your 3-week plan to Marathon Eryri
The Taper phase starts this week. Built around your fitness and adjusted every day as your form changes; attach the course and it prepares for the climbs too.
Build my planFree to start · No credit card
Marathon Eryri is a demanding and spectacular marathon that encircles Yr Wyddfa (Snowdon), Wales’ and England’s highest peak.
What this race demands
Marathon Eryri requires sustaining running output over a full marathon distance around the highest peak in Wales and England. The October timing in Great Britain means athletes must prepare for cool and potentially wet autumn mountain conditions.
Distance endurance
The standard marathon distance of 42.2 km demands thorough aerobic conditioning and structural resilience to sustain forward progress over several hours.
Mountain terrain
Encircling Yr Wyddfa requires continuous management of demanding topographical changes, placing significant mechanical load on the lower limbs during sustained climbing and descending.
Weather resilience
An October event in the Welsh mountains exposes runners to low temperatures, wind, and precipitation, requiring careful thermal regulation and fueling management.
A marathon duration exceeding two and a half hours requires consistent intake of 60 to 90 grams of carbohydrates per hour to maintain glycogen availability.
What would it take you?
Pick the level closest to yours for an estimate of finish time on this course and the training a solid preparation needs.
Estimated finish
4:30–5:25
Peak-week training
5–7 h/week
A model estimate from distance, climbing and level, not a promise. Conditions, drafting and pacing move it.
IntervalCoach turns those weekly hours into a concrete plan built around your actual fitness. Start with this race as your goal
Your road to race day
Race day at Marathon Eryri is 3 weeks away. This is how a coach divides that time. The first phase starts now.
01Taper2 weeks · Oct 4, 2026 – Oct 17, 2026
Volume drops while intensity stays: short, sharp efforts keep the legs awake as fatigue drains away.
02Race week1 week · Oct 18, 2026 – Oct 24, 2026
Openers, rest and logistics. The work is done; the job now is arriving fresh.
Frequently asked questions
When is Marathon Eryri?
Marathon Eryri takes place on Sat, Oct 24, 2026 in Llanberis, United Kingdom.
How long is Marathon Eryri?
The main route is 42.2 km.
What does Marathon Eryri demand?
Marathon Eryri requires sustaining running output over a full marathon distance around the highest peak in Wales and England. The October timing in Great Britain means athletes must prepare for cool and potentially wet autumn mountain conditions.
How much climbing does Marathon Eryri have?
Marathon Eryri has 823 m of climbing.
Who is Marathon Eryri for?
Marathon Eryri is open to all participants.
Similar races
Organising this race?