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, and Bwlch y Groes-scale effort at Pen-y-Pass. 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.
Last updated 2026-07-03 · confirm dates & 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, and Bwlch y Groes-scale effort at Pen-y-Pass.
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:
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, and Bwlch y Groes-scale effort at Pen-y-Pass.
- 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.
