Thames Ring 250

The Thames Ring 250 is a challenging 250-mile (approximately 256 miles) trail ultramarathon starting and finishing in Streatley-on-Thames, UK. The race follows an anti-clockwise loop along the Thames, the Grand Union Canal, and the Oxford Canal, primarily on flat canal and riverside paths. Despite the flat terrain, the event is tough, testing endurance over 100 hours with minimal sleep and night running.

Runners navigate using maps and GPS, supported by checkpoints every 25 miles offering food, rest, and medical aid. The race prohibits outside support except at checkpoints, emphasizing self-sufficiency. It is the UK's first race of this distance and was once Europe's longest non-stop race. Visit the organization's website for the most recent information.