River Thames Half Marathon

The River Thames Half Marathon takes place on 25 October 2026 in Walton-on-Thames. There is a single race on the programme: a 21.1 km road half marathon starting at 8:30am. No elevation gain has been published for the course.

The race name points to a route linked to the Thames, which suggests a fairly gentle profile that lends itself to even pacing. It is the kind of event where a fast time is a realistic target: two 10 km blocks run at the same speed are worth more than a first third taken out too quickly. For runners tackling their first half, a sensible goal is to finish without walking, settling into the pace of their long training runs. The morning start means arriving early enough for a proper warm-up.