Thames Ring 250

Streatley, United Kingdom • 22 Apr 2026

The Thames Ring 250 is an iconic 250+ mile ultramarathon loop starting from Goring, following the River Thames into London, then along the Grand Union Canal and back down the Oxford Canal to the finish. Established in 2009, it was the first race of its kind, known for its challenging course and high difficulty, with a completion time limit of 100 hours. Checkpoints are placed every 25 miles, offering well-stocked aid stations and rest tents, though the clock continues running during breaks. The event features tracking, first aid support, and awards finishers with a distinctive heavy medal. The course record is just under 60 hours. Visit the organization's website for the most recent information.

Race information

250 mi
250 Mile Loop
Visit the organization's website for the most recent information.
Trail runs nearby

Royston In Blue is a 5-kilometre fun run and walk held in Royston, Hertfordshire, on a two-lap trail course over Royston Heath. The undulating route offers a scenic and challenging experience for participants. The event supports the Teenage Cancer Trust, combining fitness with fundraising.Facilities..

The Full Essex Way Ultra is an 82-mile ultra-marathon starting at Epping tube station in London and finishing at the historic high lighthouse in Harwich. The race follows the entire Essex Way trail, featuring mixed terrain including trails, footpaths, tracks, and roads, with a total elevation gain o..

UTMB Index

The ATW Odyssey 12 is an exciting running event that combines physical challenge with personal growth, set against the scenic multi-terrain paths of St Neots. Participants can compete solo, in pairs, or as teams of up to six, tackling a 7km lap course. The event encourages camaraderie and support, f..

The Bishop's Stortford Mitre 10k, 5k & 1K is a community road race held at Jobbers Wood, Much Hadham, Hertfordshire. Open to all ages and abilities, the event features professionally measured 10k and 5k courses through scenic, traffic-free East Hertfordshire villages with gentle undulations. The rac..

The Chiltern Ridge Half Marathon, organized by Runaway Racing, is a challenging 21.1 km trail race held along The Ridgeway National Trail in Buckinghamshire, between Wendover and Princes Risborough. Starting and finishing in Wendover, the course features an undulating forest loop at Whiteleaf Hill N..

UTMB Index

Race to the Stones is the UK's largest ultramarathon, held along the ancient Ridgeway trail from Lewknor to the 5,000-year-old Avebury Standing Stones, a UNESCO World Heritage site. Covering 100 kilometers with 1,340 meters of elevation, the event offers a non-stop challenge or a two-day option with..

UTMB Index