Three Thames Ultra Challenges return in September 2026, with 10k, 25k, 50k, 75k and 100k routes through London and along the river.
London has many ways to spend a September weekend; walking 100km is among the less restful.
The Thames Ultra Challenges return from 11–13 September 2026 with three events spanning a night-time city loop, a 25km bridge-hopping trek and a full 100km push from Putney towards Henley-upon-Thames. Thousands are expected to take part, many with charity fundraising attached to the miles.
Three events, one long weekend on the Thames
The format is broad enough to accommodate ambition without pretending every participant has been secretly training for an ultramarathon. Across the weekend, distances range from 10k to 100k, with runners and walkers able to choose a challenge that fits their appetite, legs and willingness to regard a banana at a rest stop as fine dining.
The events sit within the wider Ultra Challenge Series. Organisers say last year’s series raised more than £15m for charity, with many entrants supporting causes that matter personally to them. Entries for this September remain available, while 2027 registration has also opened.
Thames Path Challenge stretches from Putney to Henley
The headline test is the Thames Path Challenge on 12–13 September. More than 3,000 participants are already signed up, according to organisers, with the full route covering 100km from Putney towards Henley-upon-Thames.
There are also 25k, 50k and 75k options, plus a Henley 10k. Those tackling the full distance can complete the 100km continuously, finishing in the early hours of Sunday, or split the work into two 50km stages over the weekend.
The route follows the river west through Richmond, Hampton Court and Windsor. It is a handsome stretch of the Thames, although by kilometre 80 even the most photogenic towpath may struggle to command undivided attention.
Thames Moonlight 10 puts London under the lights
The weekend begins on Friday 11 September with the Thames Moonlight 10, which offers a 10k loop and a longer 10-mile route from The Oval.
Both courses pass London landmarks including St Paul’s Cathedral, Westminster Abbey and the London Eye, with the city shifting from evening light into darkness as participants make their way around the route. It is the least intimidating of the three events and arguably the most social, particularly for friends, families or colleagues who prefer their endurance with a recognisable skyline.
At the finish, organisers are promising hot food, a glass of fizz and a moon-themed medal. After ten miles on foot, the first of those may prove the most persuasive.
Thames Bridges Trek adds a human story to the miles
Saturday’s Thames Bridges Trek takes 2,500 walkers over 25km from Putney Bridge to Southwark Park, crossing 16 historic bridges along the way. The route zig-zags across the river, pauses at The Oval for a halfway rest, then finishes after Tower Bridge.
Among this year’s participants is TV presenter, author and charity founder Katie Piper OBE, who will walk alongside fellow burns survivors from the Katie Piper Foundation community. Piper founded the charity following her own recovery from life-changing burns injuries.
That gives the trek a significance beyond scenery and step counts. For many entrants across the Thames Ultra Challenges, the physical target is only half the story; the fundraising cause is the thing that gets them to the start line and, rather more importantly, keeps them moving once the novelty has worn off.
Support becomes important as the kilometres accumulate
Organisers say all three events will include marked routes, rest stops, food and drink provision and medical teams.
Those details sound mundane beside bridges, medals and moonlight, but endurance events are usually decided in the unglamorous margins: navigation, fuelling, foot care and having somewhere sensible to stop before a small problem becomes a large one.
The three Thames events therefore offer distinctly different versions of the same proposition. Friday is urban and after-dark, Saturday’s bridges route is compact and communal, while the Thames Path Challenge is the serious test, extending deep into the weekend and well beyond central London.
There are easier ways to see the Thames. Few are likely to leave quite the same impression on the soles of your feet.
