What to Wear in a Sauna: UK Gyms, Spas, Home and Infrared

In a UK gym, leisure centre or hotel spa sauna, wear your swimwear and sit on a towel. That's the answer for nine visits out of ten. Many German, Austrian and Dutch saunas are textile-free, meaning you go in naked and wear only the towel you're sitting on, and some UK spas copy that in signposted areas. At home it's your call: swimwear, a towel wrap or nothing at all. What you should never wear is gym kit, trainers, metal jewellery or a sauna suit, and the reasons are more practical than they sound.

Public gym and leisure-centre saunas

Most UK public saunas sit next to a pool, so swimwear is the default and it's often written into the rules. A plain costume, bikini or swim shorts is ideal. They're quick-drying, they don't hold much sweat, and you're already wearing them if you've come straight from a swim.

Bring two towels if you can. One goes on the bench under everything that touches the wood (back, bum, thighs and feet if you lie down), and the second is for drying off afterwards. Sitting directly on the bench is the single thing regulars complain about most; our sauna etiquette guide covers the rest of the unwritten rules.

Should you rinse your swimwear between pool and sauna? Yes, along with yourself. Chlorine smells far stronger once it heats up.

Spas and continental saunas

This is where people get caught out. In Germany and much of northern Europe, saunas are often textile-free and wearing a costume can be considered unhygienic, because swimwear may carry pool chemicals and trap sweat. You'll typically wear a bathrobe and sliders between rooms, take the robe off at the door, and sit or lie fully on a large towel.

UK spas vary. Some keep everything swimwear-only, some run naked sessions on certain evenings, and a few have textile-free zones within a bigger thermal suite. Check the website or ask at reception rather than guessing; nobody minds the question, and getting it wrong in either direction is awkward.

Home saunas

Nobody's checking, so wear what makes you comfortable. Plenty of people use a cotton towel wrapped round the waist or chest, or go naked. If you'd rather wear something, choose loose cotton or linen, because natural fibres breathe and dry reasonably fast.

The towel-on-the-bench habit still pays off at home. Sweat soaks into untreated wood and slowly stains and smells, so a towel protects the cabin as much as it protects you. If you're still choosing a cabin or barrel for the garden, our best home sauna UK roundup compares sizes and heaters.

Infrared saunas and sauna blankets

An infrared cabin runs cooler than a traditional sauna, usually 45 to 65°C, but the dress code is the same in public: swimwear plus a towel. At home you can wear a little more if you like, since the lower air temperature makes a light cotton T-shirt bearable.

Sauna blankets are the exception. You're lying inside a heated sleeping-bag-style wrap, so most manufacturers tell you to wear loose cotton long sleeves and long bottoms to keep bare skin off the inner layer and soak up sweat. A cotton tracksuit works well; a towel underneath you saves the blanket lining. We go through models and their instructions in our best sauna blanket UK guide.

What not to wear

Some of this is etiquette, but most of it is about heat. A traditional sauna runs at 70 to 100°C (more on that in our sauna temperature guide), and anything on your body heats up with you.

Metal jewellery and watches. Rings, chains, piercings and metal watch straps absorb heat and can get hot enough to sting or mark your skin. Earrings are the usual culprit because hot air collects at head height. Take it all off and leave it in your locker; a silicone sports band is the one thing most people get away with, and many smartwatches list a maximum operating temperature well below sauna heat anyway.

Gym kit and synthetics. Polyester and nylon training gear is designed to wick sweat during exercise, not to sit at 80°C. It traps heat against your skin, clings once wet, and brings a workout's worth of sweat onto a shared bench. Cotton T-shirts are no better in a public sauna because they turn into a sweat sponge.

Trainers and outdoor shoes. They track dirt onto a floor people walk on barefoot, and they're unpleasant to wear in the heat. Leave them in the changing room.

Sauna suits. These PVC or neoprene suits are sold for "sweating off weight" and they do the opposite of what you want in a hot room. Your body cools itself by evaporating sweat; seal that sweat in and your core temperature climbs faster while you lose more fluid. Dizziness, headache, nausea and heavy sweating are early signs of heat exhaustion, and the NHS advice is to move somewhere cool and drink water straight away (NHS: heat exhaustion and heatstroke). Wear a sauna suit in a sauna and you're shortening the route to those symptoms. The kilo or so you "lose" is water, and you'll put it back on with your next drink.

Heavy make-up and fake tan. Not dangerous, just messy. They run with sweat and end up on the towel, or worse, the bench.

Flip flops, hats and other extras

Flip flops

Wear them on the walk from the changing room to the sauna door. Wet changing-room and shower floors are where foot infections like verrucas spread, so sliders are worth it purely for hygiene. Most people leave them by the door or under the bench once inside; rubber or EVA is fine, metal buckles are not.

A sauna hat

A felt or wool hat looks odd the first time you see one, but it's a regular piece of kit in Finland and Russia. Hot air rises, so your head sits in the hottest layer of the room, and a thick felt hat slows down how fast your scalp and ears heat up. It also protects coloured or dry hair. We explain how they work, and why you shouldn't treat one as a reason to stay in longer, in our guide to the sauna hat.

Glasses and contact lenses

Glasses fog the second you open the door, and metal frames get hot on your nose and ears. Plastic frames are more comfortable if you need to see, but most people leave them on the shelf outside. Contact lenses are personal: the hot, dry air makes some eyes feel gritty. If yours do, take them out before going in, and check with your optician if you're unsure about your lens type.

Hair ties and long hair

Tie long hair up with a fabric scrunchie rather than a metal clip. Wet hair dripping onto hot stones or your neighbour isn't popular.

Does what you wear change how safe it is?

A little. Anything that blocks sweat from evaporating (sauna suits, layers of synthetic clothing) raises the heat load, which is the main reason to keep it simple. Beyond clothing, the safety rules are the same whatever you wear. Sauna bathing is well tolerated by most healthy adults, according to a review in the American Journal of Medicine, which also lists unstable angina, a recent heart attack and severe aortic stenosis as reasons not to use one, and warns that alcohol during sauna use raises the risk of low blood pressure and dangerous heart rhythms (Hannuksela and Ellahham, 2001).

The long-term upside is real but mostly observational. A 2018 review in Mayo Clinic Proceedings linked regular Finnish sauna bathing with lower risk of high blood pressure, cardiovascular disease and death (Laukkanen et al., 2018). Those benefits come from going regularly, which is easier when you've got a routine sorted: costume, two towels, sliders, jewellery off, water bottle waiting outside.

If you're pregnant, have a heart condition, or take medication that affects blood pressure, ask your GP before you start. And get out the moment you feel dizzy or sick, whatever you're wearing.

Recommended reads

• Sauna etiquette: the unwritten rules for UK gyms and spas
• Sauna hat: what it does and whether you need one
• Sauna temperature: how hot a sauna should be
• Best home sauna UK
• Best sauna blanket UK