The Marathon Eryri route, printed

Marathon Eryri runs clockwise round Yr Wyddfa on roads and farm tracks, climbing to Pen-y-Pass in its first five miles and to Bwlch y Groes in its last five.

The race starts just outside Llanberis at half past ten and goes straight uphill. The A4086 climbs past Nant Peris and up the Llanberis Pass, between the crags, to the top at Pen-y-Pass, about 1,100 feet up. From there the course drops to the Pen-y-Gwryd junction and leaves the main road for the old road towards the campsite, around two kilometres of downhill farm track before it returns to tarmac. A short, steep climb lifts runners back to the main road at the campsite, and then the long descent of Nant Gwynant carries them down to Beddgelert, at about 200 feet.

The race was first run in 1982 as the Snowdonia Marathon. A local man, Ken Jones, had been inspired by the first London Marathon the year before and worked with its founders, John Disley and Chris Brasher, to set it up. He ran it again in 1983 and then handed it to the National Trust, which organised it until 2007, when it no longer had the resources to carry on. People from the surrounding villages formed a non-profit company to keep it going, and in 2023 the race took its Welsh name, Marathon Eryri. It is held in late October.

From Beddgelert the course turns north on the A4085, through Rhyd Ddu under the western flank of Yr Wyddfa and down to Waunfawr. Out of Waunfawr the route climbs quickly to Bwlch y Groes at about 1,200 feet, higher than Pen-y-Pass, with a short stretch on an unsurfaced track near the top. After the climb there is nothing left but the descent, steep and long, back down into Llanberis and the finish.