Open water swim sessions

Our Open water swimming (OWS) is extremely popular and takes place in Ardingly Reservoir between May and September. We swim laps of a 250 to 400m course depending on the water temperature. 

All swimmers must wear a wetsuit and visible swim cap unless otherwise directed.

Swims are pre-booked using the session booking page. Any swimmer who has not pre-booked and paid for their session will not be allowed in the water. Members can bring along a guest and we also offer Taster swims - see below.


OWS safety is very important to us and to take part you must:

  • Be a current member of the club
  • Read the risk assessments and club policies
  • Accept the indemnity waiver during registration
  • Take a turn as Safety Spotter on the pontoon or as a Kayaker on the water during the season


Open Water Swim Documents REQUIRED READING

Please also check out our safety video before coming to the reservoir. 



The cost per swim to club members is £5 and sessions are booked in the usual way via the Book a Session page on the MSTC website.  

You can book any session up to the session time itself. If you need to cancel then this must be done at least 12 hours in advance to get a refund. If you have any issues with this please contact


Times and Dates

The 2024 season will run from Saturday 4th May to Saturday 28th September, water temperature and quality permitting. In very dry summers the season may also be curtailed due to lack of water. Sessions times are as follows:

  • Saturday mornings 08:15-9:45
  • Tuesday evenings 18:00-19:30 

The water temperature is usually around 12-15C at the start of the season, rising to (hopefully!) low 20s in July/August and then cools quickly in September.



The club is responsible for the safety cover of all OWS sessions and follows BTF guidelines which require a Spotter on the jetty and 2 kayakers (or 1 if less than 20 swimmers) on the water watching over the swimmers at all times. Ardingly Activity Centre provide a launch and First Aid.

Everyone that swims is expected to do either a Spotter or a Kayak duty at some point in the season. These duties are allocated randomly via 3rd Party Dutyman software, and you will receive an email with your duty date and type once they have been assigned. Duties can be swapped if the chosen dates prove to be inconvenient or if a different duty is desired. We do recognise that some members may have issues fulfilling this requirement - if so then contact Debbie at

Failure to turn up for your duty means that someone else has to cover this role and we reserve the right to bar members from swimming for duty no-shows.

  • You can login directly to Dutyman here Dutyman MSTC Rota to check your duties or arrange a swap
  • Please use the reminder feature on dutyman if you forgot your password.
  • If you do not receive any emails there are some tips to help  dutyman email tips


Taster Sessions

We offer a free taster session for those who would like to try OWS before they commit to joining the club. We require you to be able swim at least 400m continuously (front crawl or breast stroke). A club member will accompany you round the first lap for safety and encouragement and you will be given a tow float to use for safety purposes. Don’t forget that you’ll need to be wearing a wetsuit and swim cap. Contact to book a slot. You will be required to sign an indemnity form before swimming.


Guest Sessions

Members can bring along a guest who needs to be booked in and paid for ahead of the session. Members are responsible for making sure that their guest knows the emergency action plan and what to do in the event of an incident. Guests will be required to sign an indemnity form before swimming.