The Grafham Water Trail Races make their debut on Sunday 11 October 2026, adding a new Cambridgeshire event to the Race Harborough calendar with 10K and Half Marathon distances around the reservoir and surrounding countryside.

Both races start and finish at Marlow Park, with the Half Marathon setting off at 9:00am and the 10K following at 9:15am. The shorter distance has been designed as an introduction to trail running, while the Half Marathon provides a bigger challenge for runners looking to increase their distance or build their trail experience.

The routes initially head west towards Easton, picking up local trails and sections of the Three Shires Way long distance bridleway. The 10K eventually loops back towards the outward route, while Half Marathon runners continue onto a large circuit of Grafham Water. Both courses will be fully marked and marshalled, with water stations along the way, although runners need to bring their own cup as the races are cupless.

Trail shoes or footwear with good grip are advised, and Half Marathon runners must carry a fully charged mobile phone. There is a generous four hour cut off for both distances, with prizes for the leading three male and female runners and a specially commissioned medal for every finisher. Race photographs will also be available as free digital downloads.

As a brand new event there are no previous winners or course records to chase just yet. On 11 October, Grafham Water's first benchmarks will be set.

Enter now via the runABC race hub.

Image courtesy Race Harborough.