Choose and Research Your Swim Spot

Check conditions before you goAlways check the weather, tide and currents before you set off.
Ask local clubs or lifeguards about the specific venueIf you're swimming in a new area, ask for advice from local open water swimming clubs.
Identify entry and exit points before entering the waterInclude a backup exit if current or tide pushes you off course.
Note water temperature for the season if year round in ukOpen water in the UK can remain very cold all year round, even if the weather is warm.
Avoid swimming aloneSwim with company, it's safer.
Avoid entry due to possible blue-green algae bloom risk if visible scum discoloration or musty smellApplies if visiting a lake or reservoir with visible scum, discoloration, or a musty smell.

Gear Up

Wear a wetsuitIt'll help you stay warm and can increase your buoyancy, so you can stay in the water for longer, and will keep you warmer and reduce the risk of shock.
Wear a brightly coloured swim hat for visibility to other water users and rescuersWear a brightly coloured swimming hat and take a tow float with you when sea swimming or dipping.
Take a tow floatProvides a resting point and makes you visible to boats and lifeguards.
Carry a means of calling for helpYou should always carry a means of calling for help when sea swimming or cold water dipping, this could be a mobile phone in a waterproof pouch.
Install a tracking app that shares your location with someone ashore if swimming regularly or in remote spotsIt can track your swim and alert emergency contacts if you fail to return home on time.

Enter graduallyOn entry, cold water causes you to gasp followed by increasing breathing and heart rate; you should get in slowly, and take 60–90 seconds to regain control of your breathing before putting your face in or swimming out of your depth.
Know the cold water shock thresholdCold water shock is a physical response to rapid entry into water that's 15°C or lower.
Recognize that fitness offers no protectionCold water shock can happen to anyone, even if you're fit and healthy, and it can happen in any kind of open water: the sea, rivers, lakes and lochs.
Limit time in cold water and build tolerance gradually rather than plunging into long swims from the startEnter the water gradually and limit your time in cold water.

Fight the instinct to swim hard if shockedIf this happens, fight your instinct to swim, turn onto your back and tilt your head back in the water, submerging your ears, relax and try to breathe normally, using your hands to help you stay afloat, wait until the shock passes then call for help or swim to safety.
Rest on your back if tiredWhen open water swimming, you might get tired, roll on to your back to rest and hold on to something that floats, like your tow float, then you can signal for help if needed.
Watch for cold-water symptoms in yourself and companionsEntering cold water very quickly can cause you to find yourself gasping for air and breathing up to 10 times faster than normal, which can cause a heart attack even if you're in good health.
Sight regularly toward your exit point or a fixed landmarkHelps avoid drifting off course, especially in tide or current.
Bail out at the first sign something feels wrongIf a swim doesn't feel right there is no shame in getting out of the water straight away, or not entering.

Call for coastguard/emergency help immediately if you or someone else is in troubleIn case of an emergency, call 999 or 112 and ask for the coastguard.
Keep trying even without signalIf you don't have any mobile phone signal, don't panic, you can still try calling 999 or 112, even if your own mobile phone network has no coverage, as your phone will try to connect to any other network available.

Rewarm gradually with warm (not hot) drinks and dry layersAvoid alcohol immediately after cold swims, as afterdrop can continue lowering core temperature for up to 30 minutes post-exit.
Debrief with your swim buddy on any hazards spottedCurrents, debris, wildlife — to inform future trips.
Review and reset your plan for next timeReconfirm tides/weather rather than assuming yesterday's conditions still apply, since conditions should always be checked before you set off for each swim.