Races Marathon · Llanberis, UK
Marathon Eryri (Snowdonia)
Marathon Eryri (Snowdonia) is a hilly marathon in Llanberis, UK, held each October. A legendary lap of Yr Wyddfa (Snowdon) — big road climbs, big descents, the long early climb to Pen-y-Pass and the late pull from Waunfawr to Bwlch y Groes. Late October in the mountains: 3-10C with rain and wind always possible. Llanberis's hills change the plan itself: expect hill repetitions and long runs that rehearse the course's shape.
Page rebuilt 2026-10-01 · race facts not independently verified — confirm dates and entries on the official race site
When
October
every year
Course
hilly
Marathon
Conditions
Late October in the mountains: 3-10C with rain and wind always possible.
Racing this course well
A legendary lap of Yr Wyddfa (Snowdon) — big road climbs, big descents, the long early climb to Pen-y-Pass and the late pull from Waunfawr to Bwlch y Groes.
Llanberis's hills change the plan itself: expect hill repetitions and long runs that rehearse the course's shape.
Pick your goal for Llanberis
Pace charts, weekly structure and timelines for the most common marathon goals:
We don’t hold a confirmed date for this edition, so any countdown comes from the date you enter here.
Build your training around Marathon Eryri (Snowdonia).
RunV works backwards from race day to today and rearranges the weeks when life interrupts. It does not adapt to this specific course — the pacing guidance above is where the course knowledge is.
Everything above stays free and complete — this is an optional next step, not a paywall.
Asked often
- When is the Marathon Eryri (Snowdonia)?
- It is held each October in Llanberis, UK. Check the official Marathon Eryri (Snowdonia) site for the exact date and entry windows.
- Is the Marathon Eryri (Snowdonia) course flat?
- A legendary lap of Yr Wyddfa (Snowdon) — big road climbs, big descents, the long early climb to Pen-y-Pass and the late pull from Waunfawr to Bwlch y Groes.
- How should I train for the Marathon Eryri (Snowdonia)?
- Train specifically for Llanberis — terrain, conditions, goal pace — and let the plan flex around real life. That's exactly what RunV's engine does after every run you log.
Not sure what to target? Predict your marathon time from a recent race →
More marathon races
Build for Llanberis — around your actual life
RunV engineers your block backwards from race day in October — and rebuilds it every time training doesn't go to script.
