THE FABRICS

Roughly eight million pieces of plastic enter the ocean every day — about twelve million tonnes a year, the equivalent of a truckload a minute. Swimwear is a small part of that in tonnage and a disproportionate part of it in symbolism, because it is the one garment worn directly in the water it pollutes. This page covers what the alternatives are actually made of.

Why the fibre matters more here than elsewhere

A swimsuit has an unusually demanding specification. It must stretch in every direction and recover, hold shape when saturated, dry fast, resist chlorine, salt and sunscreen, and survive ultraviolet light. For most of the last sixty years only nylon and elastane could do all of that, and both are made from oil. That is the starting point for everything that follows.

The second issue is shedding. Synthetic textiles release microfibres when they are washed, and swimwear is rinsed after nearly every wear. Changing the feedstock of the fibre does not change that behaviour: regenerated nylon sheds like virgin nylon, because chemically it is the same polymer. This is worth saying plainly, because it is the part most often left out.

ECONYL® regenerated nylon

ECONYL is a nylon 6 yarn made entirely from nylon waste: discarded fishing nets, fabric scraps, carpet flooring and industrial plastic collected from around the world. The waste is depolymerised back to caprolactam — the monomer nylon is built from — purified, and then repolymerised. Because the process returns the material to monomer rather than simply melting and re-spinning it, the output is chemically identical to nylon made from oil, with no loss of quality, and it can in principle go through the same loop again.

The claimed benefit is a reduction of up to 90 per cent in the global warming impact of the fibre compared with the petroleum route. That figure comes from the producer's own life-cycle assessment and refers to the fibre alone, not to a finished garment — dyeing, knitting, making up and shipping are not in it. It is a real and substantial improvement, and it is not the whole footprint of a swimsuit.

The yarn is spun in Italy and is generally rated as a high-quality technical fibre for performance swimwear, typically knitted with elastane and finished to UPF 50+ for ultraviolet protection. The elastane content, incidentally, is the part that is not regenerated: recycled elastane at commercial scale does not yet really exist, which is why almost every "recycled" swimsuit is a blend.

TENCEL™ lyocell and modal

TENCEL is a cellulosic fibre made from wood pulp in a closed-loop process: the solvent that dissolves the pulp is recovered and reused rather than discharged, which is the main distinction between lyocell and older viscose manufacture. Resource efficiency is high and the effluent problem that dogs conventional viscose is largely designed out.

As a fabric it is cool to the touch, breathes better than most synthetics and absorbs moisture more efficiently, which also gives it better antibacterial behaviour in wear. It has been certified biodegradable and compostable under industrial, home, soil and marine conditions, so at end of life it can return to nature rather than persisting. That makes it a good choice for the layers worn over swimwear, and a poor one for the swimsuit itself — it has no useful stretch recovery and it holds water.

Organic linen

Linen is made from flax, a crop that needs comparatively little water and few inputs, and which produces a fibre that is naturally biodegradable and recyclable. OEKO-TEX® certification on a linen fabric certifies the absence of a defined list of harmful substances in the finished textile — it is a chemical safety standard, not an environmental or social one, and it is worth knowing the difference.

Its properties suit exactly the role it usually plays: breathable and highly absorbent, comfortable over a wet swimsuit or on a hot day, and it improves rather than degrades with washing. It creases, which is a matter of taste rather than a defect.

Buy less, buy better — why the cliché is right

Across the life-cycle studies of clothing, one finding is consistent enough to be treated as settled: extending the service life of a garment is the largest single lever available to the person wearing it. Doubling the life of a garment from one year to two reduces the emissions associated with producing and disposing of it by roughly a quarter. No fibre substitution available today matches that.

For swimwear the practical implications are specific. Look for double lining through the body, enclosed rather than topstitched elastic at the leg and back openings, flatlock or bonded seams rather than serged ones, and coated or moulded hardware instead of bare metal. Then look after it: rinse in cold fresh water immediately after every swim, press rather than wring, dry flat in the shade, and rotate between two suits if you swim regularly, because elastane needs a day to recover.

A note on certification