Posted in Swim

Thinking about going for a dip? Here's how to prepare for open-water swimming in rivers, lakes and the sea.

Open water swimming (OWS) also known as wild swimming is more than a fad. Due to the pandemic and closure of pools, more people than ever have taken to swimming outside. Outdoor Swimmer Magazine's 2021 survey estimates "participation in outdoor swimming in the UK has increased by between 1.5 and 3 times since 2019". That's a whole lot of newbies... and if you're one of them, here's how to prepare, including essential pieces of kit.

Wetsuit or skins?

Whether or not you feel the need to wear a wetsuit will likely depend on the time of year that you are starting your journey into open water swimming. In the height of summer for example, when water temperatures are ambient, you may opt to simply wear a swimming costume or shorts. For those who want to carry on swimming into other seasons and who haven't quite built up a tolerance to the cold, we recommend a wetsuit. Not only will this will help to keep you warmer and be able to swim for longer, a wetsuit will also give you buoyancy which helps if you start to feel a little tired.

What temperatures should I expect?

So you can gauge temperature and get an idea of what we mean, 25 to 30 degrees is swimming pool temperature. Even in the height of summer, open water in the UK will be cooler than this, so here's what to expect. 

20 to 25 degrees - This temperature is balmy, but found more so in lakes during the summer than the sea - you can get away with wearing a swimming costume or shorts here.

15 to 20 degrees - If we're lucky, the English channel might reach this temp during the summer and wetsuits are optional 'It's alright once you're in'.

10 to 15 degrees - Typically late spring and autumn temperatures. Anything under 16 degrees definitely warrants a wetsuit.

0 to 10 degrees - Now we're getting into winter months and where we'd be putting on swim socks, neoprene hats and gloves too!

swimming goggles

Which tide is best for sea swimming?

The tide and wind can make for difficult sea swimming conditions and it's not ideal to be bashed about by big waves when trying to lay down your best front crawl or breaststroke. The best time to sea swim is during a 'slack tide'. This occurs roughly one to two hours either side of low and high tide and means the water will be less choppy. A great place to check the tide times and wind conditions is Magic Seaweed, where you can type in your swim location for all the latest updates. 

What equipment do I need for OWS?


dhb Aeron Women's Wetsuit 2.0A wetsuit will be key to keeping you warm, like a second skin, when you get into the water. Wearing one will enable you to stay in the water for longer. A wetsuit should be a skin-tight fit, not baggy but also not restrictive, with no excess gaps under the arms or around the knees.

dhb Aeron Women's Wetsuit 2.0

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Zoggs Original Predator Flex Polarized Goggles Exclusive

Even if you're main swim stroke doesn't involve much face-in-water action, goggles are a must to ensure your vision stays clear in salty seas or freshwater.

Zoggs Original Predator Flex Polarized Goggles Exclusive

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Swim hat

neoprene swim capSwim caps are typically worn to keep the hair out of your face whilst swimming, but during the colder seasons also keep your head and ears that bit warmer. There's nothing worse than brain freeze!

dhb Hydron Neoprene Swim Cap 2.0

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Water socks and swim gloves

Cold feet or hands can make the rest of your body feel cold too! So keep them as cosy as possible to avoid that feeling of bone ache. Swim socks and gloves will provide that extra layer from the water, similar to your wetsuit. They should feel quite tight so they don't fill up with too much water, making it hard to kick and paddle.

Zone3 Neoprene Swimming Socks

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Safety buoy/ Tow float

Open water swim spots are much larger than swimming pools and it's a good idea to be seen at all times. A safety buoy is tied around you and floats so you are visible to those around you. Many also have storage within them, perfect for holding keys and phones.

Zone3 Swim Safety Buoy and Dry Bag

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Changing robe

This is like a big hug, disguised as a towel/dressing gown when for when you get out of the water. Protect yourself from the elements and also change discreetly after your swim.

dhb Hydron Robe

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What is the best way to get in the water? 

For most people, getting into cold water can quite literally take your breath away. When you experience cold water shock, your automatic reaction is likely to be a sharp intake of breath. It is highly recommended to slowly ease yourself in, to avoid this sharp intake of breath occurring underwater. Many swimmers even dab or splash themselves with water as they go. Submerging your wrists first will also help get your body used to the temperature before fully going underwater. If you're wearing a wetsuit, it helps to let a little water into your suit (bend down hold the neck open for a few seconds). This water warms up and helps to provide a sort of barrier to the cold.

Getting in slowly is also a good idea, as sometimes cold water shock can stop your limbs from moving as they usually would. Start slowly and if you feel you are unable to swim, don't go any deeper into the water and think about getting out. 

Wild Swimming, OWS, open water swimming, sea swim
How long will I be able to swim?

The more you swim wild, the longer you will be able to stay in the water each time. This is because your body will start to acclimatise and therefore better cope with long periods of cold water immersion. You may start with just a few minutes for your first few dips. 
A great way to teach your body to cope with cold water is to carry on swimming throughout the summer and autumn, as the temperature will drop gradually each week. By the time winter hits, you will have acclimatised to colder water.

What is Afterdrop?

It is important to be aware that wild swimming does come with risks and therefore it's best to arm yourself with as much knowledge as possible. 'Afterdrop' is a common side effect of cold water swimming, where your body temperature continues to drop even after you get out. 

When you first get out of the water, you may feel fine but then your body starts to cool. You may feel faint or start to shiver uncontrollably or feel sick.

What is the best way to warm up after wild swimming?

The key to avoiding the Afterdrop is to warm up slowly and gradually. Here's how:

  • Dry off quickly & take off wet clothes ASAP
  • Change into warm clothes quickly - including hats, socks and gloves
  • Drink a warm drink whilst getting changed to help warm up from the inside
  • Eat a snack to help raise your body temperature (cake always goes down very well)
  • Don't whack the car heaters on full blast, just sitting inside to warm up slowly is best
  • Avoid a very hot shower or bath and opt for luke-warm

Wild Swimming, OWS, Open Water Swimming

Benefits of OWS

You probably already understand the physical benefits of swimming in regards to fitness and health but OWS is also linked to improving mental health and wellbeing. Cold water immersion is said to reduce the symptoms of depression and is also thought to protect our brain cells from diseases such as Alzheimer's.

Read more Benefits of Open Water Swimming

Where can I wild swim near me?

Wild swimming is a great social outdoor activity and there are many local groups for you to join. You can often find these clubs and groups on Facebook with information about where you can swim in your local area. For those who like the idea of open water swimming, but want some supervision there are many open water venues that can be found via the Outdoor Swimmer website here >>

About the author

GBurden's picture
Gabriella Burden
Published on: 13 Apr 2021

You'll find me running, swimming, cycling, or hiking. And trying to convince anyone and everyone to do the same.