4k swim
14k run
set in the organic pastures of Oxford University meadows.Starting at the medieval village of Eynsham. 1st swim from Eynsham lock, 1.2K swim. 7k run through the semi-ancient woodloands of Wytham run back to the river for 1.6k swim. Exit at king's lock 320M dash back in for the last swim, 1k downstream. Out and the final open pastures run towards the great woodland and through the tree-lined avenues towards the finish at Wytham's highest point.

Key Facts


The River Thames sets the scene for the swimming sections starting at the medieval village of Eynsham. This was the birth place of the 4K Lock to Lock swims.

Run section take you through the semi ancient Oxford University woodland of Wytham. This undulating course is almost all off road, with gentle inclines (promise!) Ok there are some hills. Great you say! Your run will take you over flat grassy section, down hills and woodland tracks.

The longer, Full stump will spend a short spell on tarmac in transition from open pastures to woodland.

Half Stump Transition
Load your transition bags at race start. These will be ready for your transition (running section) at river exit. Your bags will then be taken to the race finish for your collection.

ALL bags (full and half stump) will be taken to the finish for your collection.

This is a wonderful opportunity to join a growing sport that's basically wild and non-stop action. Totally raw running and swimming in the wild open country.

For beginners the entry level event is fantastic; if swimming is not your main discipline this will get you going, 1K swim downstream. You can relax on the run!

Already a swim runner? Use this as training for other events or go for a course record. The course is a flowing open pasture woodland mix, no public roads, completely on private land. We look forward to meeting you all on the day, wishing you a great event from all at Swim Oxford.


SwimRun Rules

1. Organiser Swim Oxford Ltd




2. Entry Pre-Requisite

All participants must be 18 years old on race day, and be able to swim and run the distance of the event you’re entering. It is your responsibility to have trained for the appropriate distance and intensity. When signing the Waiver you agree to the terms and conditions.

3. Race Course

Start.. Eynsham Lock, swimming downstream in the River Thames. Your Swim Exits will be clearly marked and marshalled. First exit point is a 1.2k swim from the start point at Eynsham Lock. Single swim category can transition from wetsuits at this point.

Collection system at the end of the race for your belongings will be in place: your wetsuit. Multiple swims category can use either Tri suit or swim run wetsuits, both are accepted. There will be either race bibs, numbered hats or timing bands. These must be kept on at all times during the event. The course will be marshalled and direction signs in place. Medical points will be in place and rescue kayaks & Safety Boats throughout the Swim routes. There are checkpoints throughout the course. Drinks and feed stations will be in place throughout the course.

4. Participants’ Equipment

You will need swim run wetsuit or tri suit, goggles, training shoes, gloves (if needed). No flippers. Skins swimmers will need a Tri suit, the start is early in the morning and water temp will be (depending on climate) 14-16 deg.

Equipment NOT allowed: Headphones, Flippers, Extra buoyancy aids (bigger than pool bouys)

5. During the Race

Participants please respect the semi ancient woodlands, these have tremendous scientific importance at Oxford University. Stay on the marked course. Your Wavier must be completed before race entry: participants are taking part at their own risk and Swim Oxford Ltd will not accept responsibility for any accidents during the event. The organiser has the right to withdraw participants who are not adhering to the guidelines or causing hazards to other participants, staff or themselves. If you want to pull out of the event you must make it known to a Marshal. Medical attention will be ready, we like to help and getting the correct information to us is very, very important.

6. Once you have finished the race/event...

...you can change into your warm clothes. Enjoy the Swim Oxford legendary cafe, offering homemade cakes and free to all Participants. There will be toilet facilities, Medical station and Ambulance. If you would like the shuttle bus back to your car you can include this with your online booking £3.50. If you decide to walk back the distance from race finish point to car park is 1.8 miles.

Schedule of events

Registration 6am-7am

Siemens Magnet Technology, Address: Wharf Road Eynsham Oxon OX29 4BP.

Race Starts 7.30am

Eynsham Lock

Safety briefings. Enjoy your swim run.

Thank you from us all

Swim Oxford Ltd is dedicated to safety and ensuring your events are well managed. On behalf of all the dedicated Swim Oxford staff, we wish you an exciting adventure on this thrilling Swim Run.

Darrin Roles

Director, Swim Oxford Ltd

Frequently asked questions:

Does the river have a fast flow?

We swim this stretch of the river regularly. The flow differs from one day to the next based on factors such as rain fall, opening of locks etc. The flow is generally fairly slow but we have noticed a difference of 15 minutes on our total swim time dependent upon flow rate. Up to date information can be found at http://riverconditions.environment-agency.gov.uk/

Which side of the river should I swim on?

The Environment Agency, who grant us permission to run the Lock to Lock events, ask that swimmers stay to the right of the river wherever possible. Boats and other river users also navigate on the right so, as river users, we need to adhere to the same rules. There are occasions when it is safer to swim closer to the middle of the river: There is one tight corner approximately 3k along the route where the water gets very shallow on the inside bend making it possible to touch the river bed. On some of the tree-lined sections of the course there can be obstacles such as submerged branches and tree roots that could be dangerous or cause injury if snagged. Our safety kayakers will help alert you to these obstacles en-route.

Do I have to wear a wetsuit?

Wetsuits are mandatory for this event unless you are an experienced open water swimmer and have our permission, in writing, in advance to swim without. Please contact us at enquiries@swimoxford.co.uk for permission.

Will the event be a timed?

The event will be timed.

When will results be available?

We aim to have results available on our website within 48 hours of the event finishing.

Will I be safe in the water?

Safety is our utmost concern. We have safety kayakers paddling with you along the length of the course and we have spotters on the shore. We also have medics at the event should you require any medical attention.

What if I feel I can’t finish the swim?

We hope that everyone will have trained enough to complete the full length of the course. However we do realise that this may be the first time some participants have swum this distance in a river and we will have support boats nearby should you experience any difficulties. There will also be exit points along the course.

Is the water clean?

The water will be tested to environmental safety standards before the swim. Since 2015 all water tests have passed with a “high” cleanliness rating.

What will the water temperature be?

The water temperature will very much depend on weather conditions leading up to the event. Water temperatures vary between 15 - 18 degrees centigrade.

Is there a chance of becoming ill during the swim?

Public Health England publish a leaflet on the risk of illness when open water swimming, which can be viewed here: https://www.gov.uk/government/publications/swim-healthy-leaflet. We always follow these guidelines and have never become unwell during or after swimming this stretch of the Thames. Public Health England recommend...Before you swim to cover cuts, scratches or sores with a waterproof plaster before swimming, consider wearing appropriate protective clothing such as a wetsuit, gloves and/or protective footwear. While you are swimming try to avoid swallowing and/or splashing water into your mouth, observe local safety advice. After swimming ensure you clean your hands thoroughly with soap and water after swimming and before handling/eating food, thoroughly clean cuts or abrasions using soap and water, handle your wetsuit with care after use, rinse it with clean water as soon as is practicable after swimming, clean with detergent and rinse as advised by the manufacturer, always wash your hands with soap and water after handling or cleaning your wetsuit and allow the suit to dry thoroughly before reuse.

Do I have to pay for parking?

Siemens Magnet Technology, very close to the start of the swim, allows us some parking spaces. There is also space for additional cars on the road leading up to Siemens. We request, where possible, that you car-share to limit the number of parking spaces being used. We cover the cost of the car park so parking is free for our competitors. There is additional, overflow parking nearby.

So I park at the start of the swim course. How do I get back to my car when I finish?

There are only 2 options...
a) Take the shuttle bus from the end of the swim back to Seimens car park. Pay for the shuttle bus when you book your ticket online. You can buy additional tickets for family or friends at registration £3.50pp (no cards accepted).

b) Walk from the finish to the car park at the start, 1.8 miles.

I’m often nervous before this type of event. What if I need the loo?

We get nervous too! There will be toilets at the start and end of the swim.

What should I do with the clothes I want to change into after the event?

Registration will take place in the field next to Eynsham Lock. There is a changing tent next to registration. Put a towel and warm clothes in a bag for the end of the swim and hand it over to our marshals. Your bag will be transported to the end of the swim ready for you to change into. There is a changing tent at the end of the swim too.

What do I do with my car keys?

We advise you to put your car keys into your clothes bag. We have a system in place to ensure that you are the only person who can retrieve your bag at the end. Please note that we cannot accept responsibility for any loss or damage to personal items left in your car.

What do I do while I’m waiting for the bus at the end of the swim?

When you’ve finished your swim and changed into your warm clothes we invite you to enjoy a fresh coffee or tea with a slice of homemade cake – included in your ticket price. Dependent upon the number of competitors at the event you should have to wait no longer than approximately 15 – 30 minutes to get a bus back to your car.

Can under 18s swim in this event?

This event is for over 18s only.

I can swim in the Thames any time for free so why do you charge?

Yes you can swim in the Thames any time, and we do, which is how we discovered this lovely stretch of the river. You can also run 26 miles through the streets of London free of charge, any day, but still thousands of people choose to enter the London Marathon each year. Our event enables you to swim in an organised swimming event and to enjoy the experience with other like-minded people. Our ticket price covers a multitude of items including… car parking, water testing, event insurance, rescue kayaks, rescue boat, paramedics, swim caps, souvenier mugs/medals, tea/coffee/cake, timing chips, WC hire, registration and changing tents, river licenses etc. It also covers the time it takes us to actually organise the event and liaise with local land owners and the Environment Agency, and our annual costs of publicising the event and maintaining our website.

What if I have more questions?

Please email us at enquiries@swimoxford.co.uk and we will endeavour to answer your questions as quickly as possible.