There is a particular kind of silence around a high tarn. No road noise, no chatter, just the lap of peat-stained water against a stony shore and the wind combing the grass. It is one of the great pleasures of walking in northern Britain — the Lakes, Snowdonia, the Cheviots, the Highlands — to arrive hot and gritty at a small sheet of water under a crag and slip in. Doing it alone adds something too: a sharper sense of your own company. But it also removes the one thing that makes wild swimming relatively safe, which is another pair of eyes on you.

Why a Tarn Is Not a Lido

A tarn is not a swimming pool with a view. It sits high, it is fed by rain and snowmelt, and it is cold all year round — often under 10°C even in August. The bottom is usually rock, silt or boulders, and it shelves unpredictably. There is no lifeguard, no buoy line, often no phone signal, and the nearest help might be two hours of rough walking away.

None of that means don't go. It means the decisions you make on the bank matter far more than they would at a lowland lake. The three that matter most are simple: tell someone exactly where you are going, carry a tow float, and do not swim alone in deep water where nobody can reach you.

Tell Someone — Properly, Not Vaguely

"Gone for a swim in the Lakes" is not a plan. Anyone waiting for you needs enough detail to raise the alarm in the right place. Before you leave the car or the tent, send a message containing:

• The name of the tarn and a grid reference, plus the name of the fell or valley it sits in.
• Your route in and out, including which car park or road end you started from.
• Your expected time back at the vehicle, and the time you expect to be home or back in signal.
• What you are wearing and carrying, especially the colour of your rucksack and tow float.
• An agreed check-in time and what they should do if you miss it: call 999, ask for the police, and say you are overdue on a fell walk — that triggers mountain rescue.

Leave a written copy on the dashboard of your car with the same details. Tell two people rather than one if you can. If your plan changes — a different tarn, a longer route — send an update while you still have signal. A missed message is far better than a search in the wrong valley.

Carry a Tow Float and Know What It Does

A tow float is the single most useful piece of kit for a solo swimmer. It is not a lifejacket and it will not keep an unconscious person afloat, but it does three things well: it makes you visible from a long way off, it gives you something to rest on, and it carries a dry bag with your phone, keys and a warm layer.

• Choose a bright colour — orange, yellow or pink, not black or dark green.
• Keep the tether short enough that the float stays beside you rather than tangling your legs.
• Practise rolling onto it in shallow water before you rely on it.
• Put your phone in a proper waterproof pouch inside, not just the float's pocket.

Where Not to Swim Alone

The rule of thumb is blunt: if you cannot stand up, and there is nobody on the bank, you are relying entirely on your own judgement and your own body to get out. Cold water takes strength quickly.

Avoid swimming solo in tarns that are deep right off the shore, in steep-sided corrie pools, near outflows where the current pulls, under waterfalls, or anywhere the exit is a slippery slab you would struggle to climb wet. Peaty water is often darker than it looks, so you cannot judge depth from the bank. If a tarn gives you a bad feeling — no easy exit, no one about, wind picking up — swim in the shallows where your feet touch, or walk on and swim another day.

Cold, Kit and Getting Out

Enter slowly. Cold water shock makes you gasp and your heart race, so give yourself a minute in the shallows to breathe before you commit. Feet first, never dive, and keep your first swims short — ten minutes is plenty in a high tarn.

Useful kit for a solo dip:

• A wetsuit or swim leggings and a neoprene top for anything longer than a quick plunge.
• Neoprene boots and a hat — most heat is lost from the head and feet.
• A big microfibre towel, a warm hat, fleece and a windproof layer waiting on the bank.
• A flask of hot drink, and a headtorch even on a summer day.
• Map, compass and whistle — the swim is the easy part of the day.

After you get out, the cold continues to pull heat from your core for up to half an hour. Dress before you eat, walk briskly, and do not sit around admiring the view in wet kit.

Walking In, Walking Out

Time your day so you are off the high ground well before dark, and check the forecast for wind and rain, not just temperature. High tarns sit in bowls that funnel weather, and a swim spot that felt sheltered on the way up can be wild on the way down. If the cloud comes in, navigate properly rather than following the path you think you remember.

Swim within your limits, tell someone where you are, float bright, and save the deep, remote water for a day when you have company. The tarn will still be there.