The Thames Marathon, now in its 9th year, is a 14km long-distance challenge swim from Henley-on-Thames to Marlow. It covers a beautiful stretch of the Thames and has become one of open water swimming’s most prestigious marathon swims.
The swim is split into 4 sections. Swimmers will be required to exit the water at the 3 locks (Hambledon at 4km, Hurley at 10km and Temple at 11.8km) where food and drink will be available.
Participants have the choice of waves – the first three waves will be for faster swimmers wanting to compete against the clock, with those expecting to finish in 3hrs 30 minutes swimming in the first wave.
There are a limited number of non-wetsuit places available. These are sold out for 2019, we are operating a waiting list. If you wish to be considered please click Enter Here on this page, and add yourself to the non-wetsuit waiting list.
- Sunday 4th August 2019
- Start location: Leander Club, Henley-on-Thames
- Finish location: Higginson Park, Marlow
- Distance: 14km river downstream
- Minimum age: 18
- Entry Fee: £106
- Tow floats will be compulsory for this event
In 2019 the Thames Marathon 14km swim will start at The Leander club, Henley and finish at Higginson Park, Marlow.
The event car park will be confirmed nearer to the event.
After you have finished your swim and had some food and collected your finisher medal, we will transport you back to this car park. The coach is included in the entry cost for swimmers. Supporters will be able to pay on the day.
We will transport one small bag (such as a rucksack or a kit bag) for each swimmer. We will tag your bag for identification purposes, and have it waiting for you at the finish area. We try and be careful but accidents do happen -please don’t use your best bag as we can’t be held responsible for any damage suffered in transit.
Absolutely, in fact we encourage it. The more people who swim together and look out for each other, the safer the event is. If you wish to swim with friends, please make sure that you all enter the same wave.
We have a fully approved safety plan that ensures coverage across the full course throughout the event. In addition ALL swimmers will be required to use a tow-float.
We have a limited number of non-wetsuit places available. This is to minimise the risk to our safety plan. Wetsuits are important for retaining heat and providing buoyancy. If you would like a non-wetsuit place your application will be assessed by the events team for approval. We advise swimmers to be prepared to wear a wetsuit if asked, on the day.
Non-wetsuit places are sold out. We are operating a waiting list.
There will be 3 feed stops in 2018 – one at each lock: Hambleden (4km), Hurley (10km) and Temple (11.8km)
We will provide a bit of everything, including bananas, energy bars, energy drinks, water, some chocolate, sweets, and some salty snacks. If you wish to use energy gel, please bring your own in your tow float, so that you know the particular brand that you use will suit you.
The faster swimmers that wish to race against the clock, will go off in the first three waves, with those expecting to finish under 3 and a half hours in the first wave. The waves will go off at intervals of 5 minutes (timetable subject to change).
In 2019 we will be setting off smaller waves at more frequent intervals of around 5 minutes starting at 7:00 am. Strong swimmers who are seeking a faster time and who expect to complete the course in under 4 hours (approximately equivalent to a sub 27-minute mile pace) will swim in the first 3 waves. If you expect your time to be under 3½ hours, please select wave 1, between 3½ and 4 hours select wave 2 or 3. Other swimmers should select wave 4, 5 or 6 – these are all mixed ability waves. If you wish to swim with a group, please ensure that you all select the same wave.
There will be a cut-off time of six and a half hours, where all swimmers will need to be out of the river. If you anticipate that you will take longer than this, please contact firstname.lastname@example.org before entering.
There are toilets at the start at Leander club, and at the finish at Higginson Park.
The route is walkable, by following The Thames Path. Download the route here – Thames Marathon Walking Route.
It is also possible to cycle the route, although there are a large number of kissing style gates where you may have to lift your bikes to get through.
Although an occasional illness can be an occupational hazard when swimming in the Thames, there were a few more than we would expect. We always test the water to ensure it falls within acceptable European bathing standards and have never had a failed test. Indeed Henley Open Water swimming club (and others) swim a number of times a week (throughout the year) on and around the same stretch and stomach upsets are extremely rare. It was particularly puzzling in that we had no recorded illnesses from the night before on the same stretch, at the Club to Pub swim. Upon further investigation it seems very likely that a combination of events contributed to the water contamination. Firstly there were some issues with old sewer pipes that are known for getting blocked, and secondly the very heavy rain fall (flash flood) on Saturday night created some flooding into the Thames. Although this is of little consolation to the individuals who suffered, it is useful for us to understand how it happened. The good news is that Thames water have replaced the old “problem” pipes.