OTT Marathon
Dol-y-Gaer, United Kingdom • 16 May 2026
OTT Marathon & 10 Mile Race
The event comprises a looped mountain marathon and a separate ten mile race based at Parkwood Dolygaer, Merthyr Tydfil. The marathon distance is described as 26.2 (ish) miles and the course passes notable features such as Pen Y Fan from Graig Fan Ddu, Fan Y Big, Talybont Reservoir and Tor y Foel. Terrain includes mountain trails with significant climbs and open views.
Distances:
- 26.2 (ish) miles marathon loop
- 10 miles alternative route via checkpoint 1
The marathon has three checkpoints located at about 7 miles, 14.5 miles and 20.5 miles. There is a cutoff at the 20.5 mile checkpoint set at six hours, which implies an approximate required pace of 18 minutes per mile or quicker. The ten mile race uses the marathon route to Checkpoint 1 then follows forestry tracks back to the finish and has one checkpoint at about 7 miles.
Minimum entry age is 18. Entries opened on 27 July 2025 and closed on 9 May 2026. Entry fees are listed separately for members and non members for each distance. All finishers receive an OTT Trail Marathon coaster and a buff.
Compulsory kit requirements are specified for each race. Marathon kit includes a charged mobile phone, minimum 1 liter hydration, foil blanket or bivvy, emergency rations, basic first aid, head torch, compass, whistle, waterproof jacket and trousers, warm layer and a reusable cup. Ten mile compulsory kit includes a first aid kit, bivvy or foil blanket, 500 ml water and a waterproof jacket. Visit the organization's website for the most recent information.