Is It Safe?

The risk profiles of wild swim spots vary, and depend on weather, waterflow and you as a swimmer. Here are some questions to get you started

River Stainforth

As an outdoor swimmer “is it safe?” should be one of the first questions you ask yourself.  No one is responsible for you when you swim outdoors but yourself, so learning how to assess the safety of a wild swim before you get in is key.

The risk profiles of wild swims vary. At the ‘less risky’ end are warm shallow lakes and river pools, which operate much like outdoor swimming pools – the temperature, water purity and underwater obstructions may be new, but the water itself is still. At the ‘more risky’ end is moving water with strong currents and tides. Swim spots that are safe one day can be treacherous the next, as a result of changing water levels or weather, for example. The way you swim affects your risk too: ‘more risky’ activities include jumping.

Any outdoor sport – such as climbing, hiking, surfing or skiing – involves a gradual acquisition of information about terrain. The core belief of the Outdoor Swimming Society is that swimmers should remain free to swim wild, but they they are entirely responsible for themselves as they do so, and we must all do our own ‘risk assessments’ before we get in and learn to understand the terrain we are in, it’s risks and how to moderate them. . Here are some basic steps to finding a suitable place to swim:

Look where other people swim:

  • Ask in the area about where people swim. It’s amazing how many locals – whether they swim or not – will know where the best swimming holes are. Teenage boys are a particularly rich source of information, being geographically restrained to one area most of the time and keen on having a good time.
  • Read Wild Swim, by Kate Rew (OSS Founder and Director), which has hundreds of wild swims around the country, plus a complete directory of lidos.
  • Join the Outdoor Swimming Society Facebook group and search for key place names or ask other swimmers.

Check it out for yourself:

When you’re standing by a potential swim spot, watch the water closely for a while and see what’s happening. Remember that you’re in an unregulated environment where things can change from day to day. Rocks move, trees fall. Which way is the water moving, and how fast? Does it look dangerous or safe?

Still and slow moving water carries lower risk than fast moving water or ones with a tide. At the beach, swimming on an incoming tide (so in the tide phase from low tide to high tide) means the tide is helping keep you on the shore. Never swim out to sea on an outgoing tide – the way back in may be impossible.

In a river, there is a basic rule: if you can’t swim upstream against the flow of water, you will not be able to get back to your entry point, and may struggle to get out of the water of downstream obstructions (such as bridges and fallen trees).

Also look at the water – does it look clean or dirty?

Deep Water:

Swimmers like deep water. It’s only dangerous if you can’t swim, or if you’re a non-swimmer or a weak swimmer who gets caught out. So if you’re not a strong swimmer, beware of sudden changes in depth.

Jumping and Diving:

Jumping and diving carry obvious risks: hitting your head on an underwater obstruction. Check your entry spot carefully before you jump or dive in – by getting in first and seeing how deep it is. This method is only crude: if jumping from a high spot you will go deeper on entry than you have tested.

Do not assume because somewhere is a local diving spot that it is safe the day you go – if water levels are low that year or that day, there may not sufficient depth (every summer someone on the OSS team witnesses people about to jump into shallow pools without thinking about whether there’s enough water in them). Conversely, if water levels are extremely high or there’s been a storm, rocks may have moved into what was previously a safe entry spot.


See where the current is fastest, see where is shallow and where is deep, throw sticks or leaves in to check the speed of the flow.

Lance Sagar

Entry and Exit Points:

If you are doing a downstream river swim, then identify your exit point before you get in, and walk upstream on the bank to the start point. This way you can see the whole stretch of water before you get in. Make sure you can easily climb out and that your exit point is easy to get to bearing in mind the speed and position of the currents.


Check for rocks, fallen trees and other obstructions that might potentially trap a swimmer. If there are weeds, avoid them.


If you do get caught in weeds, don’t panic! Slow down, try a modified doggy paddle and gently extricate yourself without kicking or thrashing around. Avoid breast stroke as you’ll get more entangled.

The Sea:

Firstly, aim to swim on lifeguarded beaches if you’re unsure what you’re doing. Speak to the lifeguards before you get in, they are the experts. Tell them if you’re off on a swim so they can keep an eye out (but bear in mind their role is to manage the main swimming/surfing areas).

When you watch the sea before getting in, check:

  • how the waves are breaking, what type of waves they are, where the rocks are, where is weedy?
  • Can you see any rips?
  • What’s the tide doing?


Check tide timetables, and be aware swimming will usually – but not always – be easier on a slack tide (an hour either side of high or low water) when less water is moving. This means there are usually weaker currents on the slack, but again, there are exceptions; for example, rip currents tend to be strongest on surf beaches around low tide.  On an outgoing tide, it will be harder to get back to shore.

See Magic Seaweed for detailed forecasts of tide times, weather and wave and swell height and interval.

Tidal stream atlases can be bought for most coastal areas (try local sailing specialists). These will detail general speed and direction of different currents along areas of the coast at different tide levels for a tide half way between neap and spring. They are very useful when planning adventurous swims, although as always when swimming outdoors you can never be certain that the water will behave exactly as expected.


See OSS Top 10 Tips for Safe Summer Swimming, OSS Intermediate Swim Safety Tips, and browse the Survive Section.

Lynne Roper & Kate Rew