Open water swim sessions

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

Swim sessions are limited to members and guests only and are pre-booked using the event booking page. Any swimmer who has not pre-booked and paid for their session will not be allowed in the water. 

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
  • Wear a wetsuit and visible swim cap
  • Take a turn as Safety Spotter on the pontoon and a Kayaker in the water during the season

Open Water Swim Documents REQUIRED READING

If you are attending the swim sessions or doing a Spotter or Kayak duty you will need 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

A changing area is set aside for club members on the green in front of the activity centre and two changing gazebos are also available for use further along the keyside. A toilet is also available just inside the activity centre. 

Times and Dates

The 2023 season will run from Saturday 6th May to Saturday 30th 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 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.

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. 

Sea Swimming

The club has regular informal meets for sea swimming but this is arranged on an adhoc basis. See Facebook for details of any forthcoming swims.