Thames Marathon

As you glide through the final stretch, the bronze gaze of the Sir Steve Redgrave statue in Higginson Park marks your approach to the finish line, silently echoing the finish of the historic Marlow Town Regatta. This is the culmination of the Thames Marathon, a downstream endurance test that carries you through some of England’s most storied river reaches. Before the park comes into view, you pass the elegant Georgian facade of the Court Garden House, a landmark built in 1758 where local lore insists the architect momentarily forgot to include a staircase, a design quirk that required an immediate and clever addition.

A journey through time and water

The river here is governed by the ancient navigation of the Marlow Lock, a site with origins tracing back to the 14th century. As you swim, you are essentially traversing a training ground long used by local rowing clubs, where the water quality and depth are meticulously maintained for both sport and commerce. Along the banks, you might spot the 14th-century hall known as The Old Parsonage, currently holding the distinction of being the oldest inhabited building in the entire county of Buckinghamshire. Further upstream, the literary echoes of West Street linger; it was here in 1816 that Percy and Mary Shelley worked on the manuscript of Frankenstein, while nearby, Thomas Love Peacock penned Nightmare Abbey. For those seeking different challenges in the region, the Club to Pub offers a different pace in July, while the Wargrave & Shiplake Regatta Swim provides a local alternative just a day before this event in August.

Race day logistics

Scheduled for August 9, 2026, the event offers distances of 5.5km, 9km, and 13km, all flowing downstream. The logistics are substantial, necessitated by the downstream point-to-point nature of the course, which requires coach transport for swimmers to their respective start lines at Henley, Hambleden Lock, or Hurley. Entry fees start from £30, and all participants receive a numbered hat, which also serves as your identifier for the bag drop facility in Marlow. Safety is managed through three dedicated feed stops on the longest route, where you can refuel with water, energy bars, and snacks. While wetsuits are optional for the 5.5km, they are strongly encouraged for the longer distances to provide essential buoyancy and thermal regulation; applications for non-wetsuit entries are subject to organizer approval and are strictly limited. The event also maintains a firm cut-off, requiring swimmers to clear the water within six and a half hours for the full marathon, ensuring the safety of the field in these tidal-influenced river conditions.