Thames Marathon, live.

Henley to Marlow, downstream

The Thames Marathon is a downstream river swim on the Thames from Henley-on-Thames to Higginson Park in Marlow, with three distances that share one finish.

The 2027 swim is on Sunday 8 August, and the day begins at 7.00am. It is run by Henley Swim, which has organised swims on this stretch of river since 2004 and holds three events in the 2027 season.

The full marathon of about 13 km starts in Henley and is swum in four sections, with swimmers leaving the water to pass Hambleden, Hurley and Temple locks on foot. Waves start from Henley from 7.30am. The mid-distance of about 9 km starts at Hambleden Lock and covers three sections, and the half marathon of about 5.5 km starts above Hurley, where the start can only be reached on foot.

All three finish at Higginson Park in Marlow. Swimmers must be 18 or older, a tow float is compulsory, and there are feed stations along the way. Wetsuits are optional on the shorter swim, and a limited number of non-wetsuit places are offered on the full distance.

Swimmers travel by coach from the event village in Marlow to their start, and the cut off times are six and a half hours for the full marathon, five hours for the mid distance and three and a half hours for the half. Supporters can walk the route on the Thames Path, walk upstream from Higginson Park to Temple Lock and back alongside their swimmer, or wait at the event village.

On Livebib you can follow a swimmer live if they choose to share their own position from the phone they carry, for example in a tow float or on an escort boat. That position comes from the swimmer, not from the organiser's timing, and the official results are published by the organiser.