OTT Marathon

OTT Marathon & 10 Mile Race, Parkwood Dolygaer, Merthyr Tydfil

The event is a trail marathon of about 26.2 miles and a separate 10 mile race set within the Brecon Beacons. Both races start and finish at Parkwood Dolygaer and follow a looped course that passes over notable upland features and reservoirs.

The marathon route rises to Pen Y Fan via Graig Fan Ddu, continues up Fan Y Big, moves toward Talybont Reservoir, and includes the final climb to Tor y Foel. The 10 mile race follows the marathon route to Checkpoint 1 before leaving the main route to return to Dolygaer via forestry tracks. The landscape includes mountain trails, steep climbs, and open viewpoints.

Distances:

• Marathon about 26.2 miles
• 10 mile race

There are three checkpoints on the marathon course at approximately 7, 14.5, and 20.5 miles. The marathon has a six hour cutoff at the 20.5 mile checkpoint, which implies an average pace of about 18 minutes per mile to continue. The 10 mile race has one checkpoint at about 7 miles and requires runners to check in there.

Compulsory kit for the marathon includes a charged mobile phone; minimum 1 litre hydration; foil blanket or bivi bag; 400 kcal emergency rations; basic first aid; head torch; compass; whistle; waterproof jacket and trousers with taped seams; warm layer, hat and gloves; and a rucksack with a reusable cup. Compulsory kit for the 10 mile race includes a first aid kit, bivvy or foil blanket, at least 500 ml of water, a waterproof jacket, and a reusable cup.

Entries open 27 July 2025 and close 9 May 2026. Entry fees vary by race and membership status. All finishers receive a coaster and a buff. Visit the organization's website for the most recent information.