Is it safe to swim at night?

There are few things more romantic than the idea of a midnight swim: warm air, a moon on the water, the town lights behind you. We understand the pull completely. We also think it is worth being clear-eyed about what changes when the sun goes down, because almost everything that keeps a swim safe by day gets harder at night. This is a summary of official advice in our own words; follow local rules, signs and lifeguards wherever you are.

What changes after dark

• No lifeguards. Lifeguard hours are posted at most supervised beaches, and they rarely run into the night. The RLSS UK Water Safety Code advises going near water with others and swimming where a lifeguard is present, which at night is usually impossible.
• Nobody can see you. A swimmer's head in dark water is almost invisible from the shore or a boat. If you get cramp, get cold or get tired, nobody may notice.
• You can't see the water. Rip currents, which the Met Office says can carry swimmers from the shallows into deeper water, are hard enough to spot in daylight. Rocks, jellyfish, weeds, drop-offs and boats are equally hidden.
• The cold feels different. Water and air often feel colder at night, and it is harder to judge how long you have been in.
• Alcohol tends to be involved. Night swims often follow dinner and drinks. Brighton & Hove City Council's seafront advice is direct: do not enter the water if you have been drinking alcohol, and it notes that the risks rise sharply after dark.

If someone gets into trouble

• Don't go in after them. The RLSS UK code says not to enter the water to rescue someone. Throw them something that floats instead.
• Call for help. In the UK, call 999 and ask for the Coastguard at the coast; elsewhere, call the local emergency number.
• If you end up in the water yourself, Brighton & Hove's guidance describes floating to live: tilt your head back with your ears under water, relax, spread your arms and legs and control your breathing, then call for help or swim to safety.

Safer ways to enjoy the water at night

The good news is that the feeling of a night swim is available without the worst of the risk:

• Evening sessions at a lido or outdoor pool. Some lidos open late in summer, with lights, lifeguards and warm water. Our guide to lido culture is a love letter to them.
• Organised night or dawn swims. Some open-water venues run supervised sessions with safety cover and glow sticks on caps.
• Paddle at the edge. Standing knee-deep in a warm sea at night, with friends on the beach, gives you the moonlight without the hazards.
• Swim at dusk instead. The golden half hour before sunset often has the same magic, with better light and, sometimes, lifeguards still on duty.
• The hotel pool. Unglamorous to admit, glorious in practice, and often open late. Follow its rules on hours and supervision.

If you still choose to swim at night

We would rather you did not swim in open water after dark. If you are an experienced open-water swimmer and decide to anyway, these are the minimums:

• Never alone. Someone on the shore who knows exactly where you are, plus ideally a swimming partner.
• Never after drinking.
• Only water you know well by day, in calm conditions, and only if local rules permit it.
• Be visible: a bright cap, a tow float with a light, glow sticks.
• Stay close to shore and swim parallel to it, not out to sea.
• Keep it short, and get out as soon as you feel cold.

Even then, it is a risk. A great night out does not need one.