A good swim brief can last for several summers, or it can lose its shape before August is over. The difference is rarely the fabric alone. It is what happens after you get out of the water: the hour it spends rolled up in a damp towel, the hot balcony railing it dries on, the sunscreen rubbed into the waistband. Whether you swim lengths in an indoor pool in winter, spend Sundays at the lido or jump into a lake or river in July, a few simple habits keep your swimwear looking new for much longer. This guide explains what actually damages swimwear and how to care for it, step by step.
What wears out swimwear?
Most men's swim briefs and fitted swim trunks are made from a blend of polyester or nylon with elastane (also known as spandex or Lycra). Elastane gives the stretch and the snug fit; it is also the most delicate fibre in the mix. Five things break it down faster than anything else:
- Chlorine: pool water is treated to stay hygienic, and those chemicals slowly weaken elastane and fade colours.
- Heat: hot tubs, saunas, tumble dryers, radiators and very hot water make elastic fibres lose their recovery.
- UV light: hours of direct sun bleach prints and dry out the fabric.
- Sunscreen and oils: some ingredients leave yellowish marks, especially on light colours.
- Friction: rough pool edges, concrete steps and sand cause pilling and snags.
The good news: UPRO swim briefs use a polyester-elastane blend (mostly 90% polyester, 10% elastane). Polyester is generally more resistant to chlorine than nylon, so with sensible care the fabric holds its colour and shape well.
Right after swimming: rinse, don't wring
This is the single most important step. As soon as you can, rinse your swimwear in cool fresh water, even if you only swam for ten minutes. The pool showers are perfect for this. Rinsing washes out chlorine, salt, lake sediment and sunscreen before they have time to work into the fibres.
Afterwards, gently squeeze out the water. Never wring or twist the fabric, as this stretches the elastane unevenly. If you have to carry it home, roll it in a dry towel rather than leaving it in a closed plastic bag, where heat and moisture build up.
Pool, lake or river: what changes?
Indoor and outdoor pools
Chlorinated water is the toughest environment for swimwear. If you swim regularly, for example lengths before work, rinse immediately every time and consider rotating two swim briefs so each has a full day to dry and recover. Patterned swimwear like the Pastel Jellyfish Print Swim Brief also tends to show fading less than a flat, single colour.
Lakes
Fresh lake water is much gentler than pool water, but it still carries algae, fine sand and organic matter that can dull light colours. A quick rinse at home is enough. Let your swimwear dry fully before packing it away, especially after an evening swim.
Rivers
Swimming in a river is wonderful in summer, but the current pulls at your swimwear. Choose a snug fit and, ideally, a drawstring you can tighten before getting in, like on the Blue & White Striped Drawstring Swim Brief. After a river swim, rinse out any grit caught in the lining.
Sea and holidays
Salt water dries into crystals that roughen the fabric. Rinse after every swim, and avoid sitting on hot rocks or rough concrete in your swimwear.
How to wash swimwear properly
- Wash by hand in cool or lukewarm water (no more than 30 °C) with a small amount of mild detergent.
- Gently move the swimwear through the water for a minute or two and then rinse thoroughly.
- Do not use fabric softener or bleach. Softener coats the fibres and reduces stretch.
- If you must use a washing machine, choose a delicate or hand-wash cycle at 30 °C, put the swimwear in a laundry bag and skip the spin or use the lowest setting.
- Close any ties or drawstrings so they do not tangle, for example on the Tie-Side Reversible Swim Brief.
You do not need to machine-wash after every swim. A fresh-water rinse after each use and a proper hand wash every few wears is plenty.
Drying: shade, not sun
Lay your swimwear flat on a towel or hang it over a drying rack in a shaded, airy spot. Keep it away from radiators, heated towel rails and tumble dryers. Direct sun dries it quickly but fades the print; heat makes the elastane brittle. A swim brief dries surprisingly fast in the shade anyway.
Sunscreen, sitting and other small habits
- Apply sunscreen 15–20 minutes before putting on your swimwear, so it has time to absorb.
- Sit on a towel, not directly on the pool edge, wooden decking or stone.
- Avoid hot tubs in your favourite swim brief, or keep an older one for the whirlpool and sauna area.
- Give your swimwear about 24 hours between uses so the elastane can recover.
Storing swimwear over winter
At the end of the season, wash each piece by hand, let it dry completely and store it flat in a drawer or a breathable bag. Do not fold it while still damp and avoid plastic bags. Light-coloured swimwear, such as the White & Blue Shell Print Swim Brief, is best stored away from direct light so it does not yellow.
When is it time for new swimwear?
Signs that your swimwear is worn out include a baggy seat, a waistband that no longer holds, a see-through look when wet and threads of elastane poking through the surface. At that point it is time to replace it. If the old one stopped fitting because it was the wrong size from the start, check our fit and size guide before you order, and read swim briefs vs swim trunks if you are deciding between shapes.
FAQ
Can I put swimwear in the washing machine?
Occasionally, on a delicate cycle at 30 °C in a laundry bag, without fabric softener. Hand washing is gentler and is always the better choice.
Do I need to rinse swimwear after swimming in a lake?
Yes, a quick rinse in fresh tap water is a good idea. Lake water is gentle, but it can leave fine sediment and algae in the fabric.
How do I remove sunscreen stains from swimwear?
Treat the spot with a little mild detergent or dish soap in cool water, work it in gently and rinse well. Act quickly; old marks are harder to remove.
Why does my swimwear go baggy?
Usually because of heat (hot tubs, dryers, radiators), chlorine and too little time to recover between swims. Rinsing, drying in the shade and rotating two pieces helps a lot.
Looking for a new favourite? Browse our men's swim briefs, the square-cut swim trunks or the full UPRO men's swimwear collection, sizes M–XXL, each piece sold individually.