Thames Ring Series

Thames Ring Series

The Thames Ring Series consists of three non-stop ultramarathon distances run on canal and riverside footpaths in southern England. The main event is the Thames Ring 250, a 250-mile (approximately 256-mile) trail race. It was the first race of this distance in the UK and, for many years, the longest non-stop race in Europe. The route is an anti-clockwise loop starting and finishing in Streatley-on-Thames, heading east along the Thames, up the Grand Union Canal, and back via the Oxford Canal.

In 2026, the event expanded into a series with two shorter distances: the TR150 (150 miles) and the TR100 (100 miles). The TR150 covers the first part of the full route to a checkpoint in Nether Heyford. The TR100 covers the second part from Nether Heyford to the finish in Streatley.

Participants must navigate using provided maps and GPX files, as the route is not marked. The race has a total of nine checkpoints, spaced roughly 25 miles apart, offering basic hot and cold foods and drinks. Sleeping tents are available at some checkpoints after 75 miles. Changing facilities and toilets are available at the start, finish, and some checkpoints.

All runners are tracked via GPS, and an emergency SOS button is included. There is no specific qualifying criteria for entry, but runners must be 18 years or older. The cutoff times are strictly enforced: 100 hours for the TR250, 53 hours for the TR150, and 34 hours for the TR100.

Entry includes:

• GPS tracking
• Food at checkpoints
• Medical support
• Baggage transportation
• A finisher's medal for those who complete the course

Runners must be self-sufficient between checkpoints. A compulsory kit list includes the ability to carry at least 1 litre of fluids, full waterproof top and bottoms (with taped seams), a hat or buff, food, a mobile phone with charging capability, and a head torch (minimum 100 lumens). Outside support is only permitted at designated checkpoint locations; no pacers or buddy runners are allowed.

Drop bags are permitted. For the TR250 and TR150, one bag (up to 20kg) is transported to each checkpoint. For the TR100, a drop bag is only accessible at a single checkpoint halfway through the race.

Volunteers who help for more than 24 hours receive an event hoody; those volunteering for less time receive an event T-shirt or buff. Transport costs for volunteers, such as fuel or train tickets, are reimbursed after the event upon receipt submission. Visit the organization's website for the most recent information.