Thames Marathon - Henley Swim - Inspirational Swim Events - Open Water Swimming

Thames Marathon

14km long-distance challenge swim from Henley-on-Thames to Marlow



When and Where:
Sunday 4th August 2019
Leander Club, Henley-on-Thames

14km downstream

Entry Fee:

Waiting list for non-wetsuit places
Minimum age 18
Tow floats compulsory


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 energy snacks will be available.

Participants have the choice of waves – the first four 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 have all been allocated for 2019, and we are operating a waiting list.

Wetsuit places are available.

Where does the swim start and finish?

The Thames Marathon 14km swim will start at The Leander club, Henley and finish at Higginson Park, Marlow

Where should I park for the event?

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.

Is there other parking in Henley?

Yes, there are plenty of public car parks in Henley and they are free on Sundays. The return coach will only drop off at the official car park.

How will my bag get to the end?

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.

Can I swim in a team with a group of friends?

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.

Will I be able to wear a tow float?

All swimmers will be required to use a tow float and are advised to get used to swimming with one before the event. You can purchase a discounted Swim Secure tow float when you register

How will you ensure that those who want to do solo swims are able to do so safely?

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.

Can I swim non-wetsuit?

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 have all been allocated for 2019, however if you wish to swim without a wetsuit please enter our waiting list, as places do come free during the year.

How many feed stops will there be ?

There will be 3 feed stops – one at each lock: Hambleden (4km), Hurley (10km) and Temple (11.8km)

What food will be available at the feed stops?

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.

How will the start work?

The faster swimmers that wish to race against the clock, will go off in the first four 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).

How should I choose which wave to enter?

We will be setting off small waves at 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 4 waves. If you expect your time to be under 3½ hours, please select wave 1, between 3½ and 4 hours select wave 2, 3 or 3B. Other swimmers should select wave 4, 5, 6, 7 or 8 – 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 before entering.

Are there toilets on the course?

There are toilets at the start at Leander club, and at the finish at Higginson Park.

Can supporters walk the route?

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.

Can I talk to fellow swimmers in advance of the event?

Definitely, we have set up Henley Swim Chatter as a facebook forum, where you are able to discuss anything with fellow swimmers from nutrition and training tips to transport to the event on the day.