How to Choose a Sustainable Swimwear Fabric: A Buyer's Explainer
Swimwear takes a beating. Chlorine, salt, sunscreen, hot sand, the rough edge of a sea pool and a season of washing all attack the same few grams of fabric. A suit that survives three summers in Cornwall or a winter of indoor lengths is not lucky; it is well made, well chosen and reasonably well looked after.
The fabric is the part you can judge before you spend anything. Here is how the main options compare, what the labels actually mean, and how to keep a swimsuit going long enough to justify buying it in the first place.
Start with the composition label, not the story
Turn a swimsuit inside out and you will find a small care label listing percentages: usually one main fibre and a smaller stretch fibre. That label tells you more than the swing tag. A suit described as “made with recycled materials” might be 78% recycled polyamide and 22% elastane — mostly recycled, but with a fifth of it virgin, oil-based and impossible to separate from the rest. That blend is also why swimwear is so hard to recycle at the end of its life.
So read two things: how much of the fabric is recycled, and what the stretch component is. If a brand can’t tell you the percentage, that is worth knowing too.
Recycled nylon (polyamide): the all-rounder
Recycled nylon — often listed as recycled polyamide, or “regenerated nylon” — is made from waste streams such as fishing nets, carpet fibres and industrial offcuts. It is soft, smooth, holds its shape, takes dye vividly and recovers from stretching better than most alternatives, which is why it dominates well-cut one-pieces and bikinis.
The drawbacks are real but manageable. It is still plastic, its production is energy-intensive, and every wash sheds microfibres. A discarded net turned into a swimsuit is a smart use of waste, but the suit still reaches landfill eventually. Look for a certified recycled content claim and accept that the elastane blended into it will be new.
Recycled polyester: useful, but read the fine print
Most recycled polyester starts life as drinks bottles. It is tough, colourfast, dries quickly, resists chlorine and sunlight reasonably well, and costs less than recycled nylon. It also feels less soft against the skin and has weaker stretch recovery, so it is nearly always blended with elastane.
That makes it a sound choice for rash vests, board shorts, swim caps and children’s kit — pieces where durability matters more than a second-skin fit. The trade-off is that a bottle turned into fabric usually cannot go back to being a bottle, and the microfibre shedding problem is the same. It is a reasonable choice, not a perfect one.
Natural fibres and bio-based options
Cotton, linen and hemp
Lovely next to the skin and hopeless in water. Cotton absorbs it, goes heavy, dries slowly and sags out of shape; linen behaves similarly. Keep them for cover-ups, beach shirts, sarongs and sun hats, and look for organic or recycled versions where you can. If you are buying one swimsuit and one beach shirt, make the shirt the natural one.
Bio-based nylon
A growing number of fabrics use plant oils, such as castor bean oil, as the feedstock for polyamide instead of fossil fuels. The finished fabric behaves much like conventional nylon. Availability is limited and prices tend to be higher, and it still sheds microfibres and still needs elastane for stretch.
Wetsuits and rubber
If you are shopping for a wetsuit or a neoprene-style layer, ask what the rubber is made from. Plant-based rubber and limestone-based alternatives to petroleum neoprene exist, and many suits now use recycled polyester linings. Waterproofing treatments vary too, so it is worth asking rather than assuming.
One honest point: no natural fibre yet matches synthetic stretch for pool swimming. Most swimwear will be a synthetic blend, so choose the best version of that you can and then look after it.
What the certifications actually tell you
- Global Recycled Standard (GRS): third-party verification of recycled content, chain of custody and some social and environmental criteria.
- OEKO-TEX Standard 100: tests the finished fabric for harmful substances — useful for anything sitting against your skin.
- bluesign: looks at chemical use and manufacturing processes.
- EU Ecolabel: broad environmental criteria applied to textiles.
None of these guarantees a garment will last, fit well or be recyclable. Treat them as a floor rather than a finish line — helpful, but not the whole decision.
Care that keeps swimwear out of the bin
Elastane is the first thing to fail, and heat, chlorine, sunscreen and rough washing all speed that up. A few habits go a long way.
- Rinse straight after swimming in cool fresh water. It takes thirty seconds and removes most chlorine, salt and sunscreen.
- Wash gently. Hand wash with a drop of mild detergent, or use a delicate cycle at 30°C or lower inside a fine-mesh wash bag to catch loose fibres.
- Skip fabric softener, bleach and hot water. All three damage stretch fibres.
- Dry flat in the shade. Never tumble dry, never wring it out, and never leave it balled up in a wet towel.
- Rotate two suits. Giving elastane a day to recover between wears extends its life noticeably.
- Mind the surfaces. Sit on a towel rather than concrete or a rough pool edge, and keep velcro fastenings away from the fabric.
- Repurpose at the end. Worn-out suits make decent cleaning cloths, and some brands run take-back schemes worth checking.
Every wash releases microfibres, so washing less often — and using a wash bag when you do — makes a difference. It is not a complete solution, but it is better than nothing.
Choosing well: a short checklist
Before you buy, check the composition label for the recycled percentage, give the hem a gentle tug to see whether it springs back, and make sure the fit is genuinely comfortable. A suit that is slightly too tight or too loose will fail sooner than one that fits properly. Deeper colours and prints also hide sunscreen marks and fading better than pale pastels.
Then weigh the practical side. If you swim laps twice a week, a chlorine-resistant recycled polyester blend will outlast a delicate fashion piece. If you swim in the sea a handful of times a year, a well-made recycled nylon suit looked after properly could last several seasons.
Whatever you choose, fabric alone is not sun protection. Cover up, use sunscreen, stay out of the strongest midday sun and follow public health guidance — particularly for children, whose skin is more vulnerable.
Buy fewer, better suits in the fabric that matches how you actually swim, rinse them out, and wear them until they genuinely give up. That is the most sustainable option available to most of us.
Photo: Engin Akyurt / Pexels
