CADAIR X - The Cadair Idris Half Marathon

CADAIR X - The Cadair Idris Half Marathon10 May 2025

The route takes you through ancient woodland, past stunning glacial lakes, historic trails, and challenging mountainous terrain, including the summit of Cadair Idris.

Distance: 13.1 miles

Height gain: 1165m

Terrain: 65% trail, 25% mountain path, and 10% tarmac​

This is a mountain route with some challenging ascents and descents. Cut off at the summit is 90 mins after race start.

The Route

A run through the tranquil woodland of Dol Idris and then up steeply through the wooded gorge. Ascend out of the trees and clasp glimpses of the stunning glacial lake Llyn Cau to your left. Continue the ascent towards Mynydd Moel before traversing west and ascending to the summit of Cadair Idris, 893m.

The section between 1km and 3km involves a sustained ascent. It's one of the steepest starts to any race.

The most challenging underfoot terrain is just after the summit of Cadair Idris and taking care on this descent.

Once off the rocky terrain of the summit a descent will follow the established Pony Path before turning southwest down towards Tyn Y Fach and Mary Jones' Chapel.

Then follow a beautiful, less-travelled section of the Mary Jones walk before traversing North East through tranquil woodland tracks, secret waterfalls and back along a country track parallel to the north side of the stunning glacial ribbon lake, Tal Y Llyn, before returning to Cadair Tearoom for some well-earned rest.