Swimming in open water can increase your risk of illness. Rivers, harbours and coastal waters contain bacteria and other micro-organisms that can cause illness if swallowed or if they come into contact with cuts and grazes. Conditions can change quickly, so check local information before you swim.
Read national health advice from the UK Health Security Agency and GOV.UK.
Before you swim
Take the these steps before entering the water:
- swim only in designated swimming areas
- check water quality information where available
- do not swim if you are unwell or have recently had diarrhoea or vomiting
- consider avoiding swimming for several days after heavy rainfall, when pollution levels may be higher
- cover cuts and grazes with a waterproof dressing
While swimming
To reduce your risk of illness and injury, you can:
- avoid swallowing the water
- wear goggles if needed
- enter the water slowly to reduce the risk of cold water shock
After swimming
Once you have left the water:
- shower as soon as possible
- wash your hands before eating or drinking
- clean and cover any cuts or scrapes exposed to the water
Seek medical advice if you develop diarrhoea, vomiting or other symptoms after swimming, and tell the healthcare professional that you have been swimming in open water. Do not swim again until you have been free from diarrhoea for at least 48 hours, or longer if advised by a healthcare professional.
Check water quality
You can check official bathing water quality information before you swim.
You can also use the UK Live Sewage Map from Surfers Against Sewage, which provides water quality alerts using open data and information from water companies.
Sea safety
If you are swimming in the sea, follow local safety advice and be aware of changing conditions.
To stay safe:
- be aware of tides and currents
- use lifeguarded beaches where possible
- enter the water slowly and avoid jumping in, particularly in cold water
Cold water shock can cause gasping, rapid breathing and loss of control within seconds.
Follow water safety advice from the RNLI.
Further health advice
Further guidance on staying healthy while swimming in open water is available from the UK Health Security Agency and GOV.UK.