Night Swimming

The art of swimming in natural light at night

Karl Fredrickson

Night swimming is not just a badly lit version of what you do in the day: the best way to swim at night is not to add light – but to use your other senses to navigate. In an extract from The Outdoor Swimmers’ Handbook, Kate Rew shares tips (including moon-tracking apps) that help swimmers plan and execute a swim in the dark.

Raphael Rychetsky

How many visceral snapshots do we collect as we go through life, moments we can recall so precisely we can reinhabit our physical bodies where we were, decades later? I have many from night swimming. I can remember standing in the frosted ruts of a Cornish field in February with my back to the sea, startled by the clarity of my moon shadow. I can remember waving my hands around in phosphorescence in Thailand, and sitting on the bottom of an Oxford lido looking at the legs of friends underwater after we’d scaled a fence to get in at night. And I can still hear the tinkling of drowned twigs from a swim drifting down the Thames on my back in Autumn, carried by cold water into my ears. It is the important experience that is stored, and these are the moments that make the recollections of our lives.

Key to all of these memories is the fact that we weren’t just swimming at night, we were swimming in the dark, without lights. What makes it so special is that as one sense, sight, powers down others – what you hear, what you smell, what you can feel as your body moves through the water –  take their place, heightening the experience of swimming in a different way. I love the gloaming: the hour of the day when colour fall out of the world, day slips into the water, and a rich inky blue night slides in, bringing with it a stillness, a quietness: hills and trees blacken, winds fall, dew settles, stars rise, and out come the bats.

I love the gloaming: the hour of the day when colour fall out of the world, day slips into the water, and a rich inky blue night slides in, bringing with it a stillness, a quietness: hills and trees blacken, winds fall, dew settles, stars rise, and out come the bats.

 The Outdoor Swimmers’ Handbook

Cy Scammell


  • Night swimming is best done at a location where you know both the walk in and the swim well; somewhere you have the familiarity of knowing what features to pick out at night.
  • Any form of light in the water will reduce night vision so if it’s safe to swim without aids like head torches, you will see more of the stars and discern more around you.
  • Absence of colour does not mean absence of sight: if you stay away from using artificial light your eyes change the way they see and what they pick up: silhouettes of trees, bats swooping above, a sense of the path.
  • It takes 25-40 minutes for eyes to adapt to the dark – to see better (without illumination), lower screen use and torch use before you get in.
  • You will need to be able to see your exit, and while exits always look different from the water (particularly when sunk down into a river or lake), identification is ever harder when it is dark.  We did lose an exit point once and playing ‘would you rather? Get colder still or try and climb up a steep bank semi-naked using nettles as handholds?’ is not as fun as all that. Soft illumination of an exit point with a small light can be a good idea – just make sure you can see the lantern or it’s glow from down in the water.
  • If you want to see the sun rise in the morning, to swim from dark into light, google ‘astronomical dawn’ rather than ‘sunrise’. Dawn and dusk happen in stages and by sunrise (‘civil dawn’) you can see objects clearly and it will not feel like swimming from night to day at all. It is possible to look the stages of twilights online for your geographic location and time your swim accordingly.
  • A reusable adventure light in a tow float makes a great floating lantern. Dragged behind you it will add security in a group, with less effect on night vision than head torches.
  • If you are swimming in a lake or river, then gently illuminating a get out point may be useful.
  • Air temp drops quickly when the sun goes down – remember to take warm things for afterwards!
Ganapathy Kumar


  • The moon rises in the east. If there are large objects between you (sunk down in your waterway) and the horizon then they will block the view of a rising moon and you will not see it until it is higher in the sky. I have had my best views of rising moons swimming through wide open water meadows, with no objects in the foreground (except the odd curious cow) to obscure the horizon.
  • The moon looks biggest when it is close to the horizon. These moments are wonderful: it looks giant and glowing. Supermoons are when the moon appears larger as it is closer to the earth, but it appears that way rising even on ‘ordinary’ full moons.
  • Photographers apps such as Solar Watch will help you work out where the moon will rise at your chosen swim spot, and whether there will be big objects between you and in when it comes over the horizon.
  • Winter full moon swims can take place at earlier times than those in summer.
  • Remember! Full moons mean spring tides, which means bigger than average tides and swell. This introduces a lot more risk and unruliness to a night swim.
  • Light pollution – an orange haze of distant (or nearby) towns, cars and street lighting – will reduce the stars seen and moon’s luminescence. Swimming in a dark sky reserve or remote place will make swims darker and the stars brighter.
  • Moon rise varies from day to day – see the OSS full moon calendar. In 2022 the autumn moons both fall conveniently on the weekends: the September full moon (Big Moon) is on Saturday 10th September, and in October the ‘Moon Where Rivers Freeze’ (also called the Blood Moon or Hunter Moon) falls on Sunday 9th October.

The fear of getting caught,

Of recklessness and water

They cannot see me naked.

These things, they go away

Replaced by every day.


REM – Night Swimming



Kate Rew