Swimwear Fabrics: Which Material Actually Lasts in Chlorine

Choosing swimwear fabric matters more than most people realise. Get it right and a training swimsuit lasts a full season or longer. Get it wrong and the same suit is baggy, see-through and heading for the bin inside two months. This guide explains what swimwear is actually made from, why chlorine destroys some fabrics and not others, and which fabric suits which kind of swimmer.

The short answer

If you are… Choose Why
Swimming squad or laps 3+ times a week Polyester or PBT polyester Chlorine resistant — holds shape and colour through heavy pool use
An occasional pool or beach swimmer Elastane / Lycra blend Softest feel and best initial fit; chlorine life is shorter but it doesn't matter at low volume
Racing at club level or above A dedicated racesuit fabric Built for compression and speed, not longevity — see the racesuit section below
Buying for a toddler or learn-to-swim Polyester Survives warm, heavily chlorinated teaching pools, which are the harshest environment there is

Why chlorine destroys swimwear

Chlorine doesn't attack swimwear evenly. It attacks one specific ingredient: elastane, also sold under the names Lycra and spandex. Elastane is the stretchy filament woven through most conventional swimwear, and it's what gives a new suit that soft, snug, second-skin feel.

Chlorine breaks the chemical bonds in those elastane filaments. As they degrade, the fabric loses its recovery — the suit stops springing back. That's what causes the familiar sequence every swim parent knows: the suit goes baggy in the seat, the straps stretch, the colour fades, and eventually the fabric thins to the point of transparency.

Chlorine-resistant fabrics solve this by removing or reducing the vulnerable ingredient. A 100% polyester suit has no elastane for the chlorine to attack, so it keeps its shape and colour for far longer.

Worth knowing: chlorine isn't the only culprit. Heat is just as damaging, which is why spas and hot tubs kill swimwear faster than anything else. Sunscreen, body oils and rough concrete pool edges all shorten a suit's life too.

The three fabric families

Elastane and Lycra blends

Usually a nylon-elastane or polyester-elastane mix. These are the softest fabrics with the most forgiving fit, and they're what most fashion and beach swimwear is made from. The trade-off is chlorine life. In a chlorinated pool used several times a week, an elastane-blend suit will typically start losing shape within a couple of months. For beach swimming, holidays and occasional pool use, that's a perfectly sensible choice.

Polyester

The workhorse of training swimwear. Polyester has no elastane to degrade, so it resists chlorine, holds its colour and keeps its shape through heavy use. Polyester suits feel firmer than elastane blends when new and soften with wear. They also dry quickly and generally carry good UV protection.

PBT polyester

PBT is a textured polyester yarn that has natural stretch built into the fibre structure rather than borrowed from elastane. That gives you genuine four-way stretch and chlorine resistance in the same fabric — which is why PBT and polyester-PBT blends dominate serious training and racing swimwear. If you've ever wondered why a training suit can be both stretchy and long-lasting, PBT is the answer.

A note on chlorine-resistant blends that do contain elastane

The polyester-versus-elastane rule is the right starting point, but it isn't absolute. Some fabrics marketed as chlorine resistant do include elastane — Zoggs' Elastomax™, for instance, is 80% nylon and 20% elastane and is rated for around 120 pool hours, while some Ecolast™ garments run around 82% recycled polyester to 18% elastane. These achieve their resistance through fibre treatment and construction rather than by eliminating elastane altogether. They're softer than a pure polyester suit and still far more durable than ordinary swimwear — just not usually as long-lived as a 100% polyester or polyester-PBT suit. If a brand publishes a pool-hours rating, that's the most honest number to compare.

Brand fabrics compared

Each brand markets its own engineered fabric. Here's what they actually are:

Fabric Brand Composition & claims
Endurance+ Speedo 53% polyester / 47% PBT polyester. 100% chlorine resistant and, per Speedo, twenty times more fade resistant than conventional elastane swimwear. Multi-directional four-way stretch.
C-Infinity Funkita & Funky Trunks 100% Italian polyester. Chlorine resistant with exceptional strength, and retains durability well beyond conventional elastane swimwear fabrics.
MaxLife Eco Arena Highly chlorine resistant, quick-drying, UPF 50+. Made from at least 50% recycled polyester from PET bottles and certified to OEKO-TEX® STANDARD 100.
Aqualast™ Zoggs 100% chlorine proof with a lifetime fabric guarantee. Quick drying, exceptional colour and shape retention, UPF 50+. Used across the learn-to-swim and toddler range.
Ecolast™ / Ecolast+™ Zoggs A family of recycled fabrics made from post-consumer plastic bottles, rated 100% chlorine proof and covered by Zoggs' Lifetime Guarantee, with UPF 50+ and machine washability. Composition varies by garment — examples in this range run from 84% recycled polyester / 16% PBT (roughly 7.5 x 500ml bottles per metre) through to 82% recycled polyester / 18% elastane (18 bottles per metre). Ecolast+ adds compression, which Zoggs rates at around four times that of generic swimwear fabrics; one Ecolast+ suit here is 51% recycled polyester / 49% PBT at 13 bottles per metre.
Elastomax™ Zoggs 80% nylon / 20% elastane. An ultra-soft chlorine-resistant fabric rated for up to 120 pool hours, used across the modesty suit range where softness and drape matter more than maximum longevity.

All six are chlorine-resistant fabrics and any of them will outlast a standard elastane blend in a training pool. The differences between them are smaller than the difference between choosing a chlorine-resistant fabric and not choosing one.

Which fabric for which swimmer

The squad swimmer

Four to ten sessions a week is the most demanding use case there is. Polyester or polyester-PBT, without exception. Buy two suits and rotate them — a suit that gets a full day to dry between wears lasts noticeably longer than one worn damp.

The adult lap swimmer

Three or more swims a week justifies a chlorine-resistant fabric. Below that, an elastane blend is fine if you prefer the softer feel, provided you rinse it properly.

The learn-to-swim child

Teaching pools are warm and heavily chlorinated — the toughest conditions for fabric. Polyester every time, and expect to size up as they grow rather than expecting one suit to stretch.

The beach and holiday swimmer

Salt water and sunshine are far kinder to swimwear than chlorine. Choose whatever fits and looks best; fabric technology matters much less here.

Racesuits are the exception

Competition racesuits — sometimes called tech suits — follow completely different rules. They're built from bonded, highly compressive fabrics engineered to shape the body, reduce drag and repel water. Longevity is deliberately not the goal. A racesuit is designed for a limited number of races, not for daily training, and wearing one to squad sessions will destroy an expensive piece of kit in weeks.

Treat a racesuit as race-day equipment: rinse it in cold fresh water immediately after every swim, dry it flat away from sunlight, and never put it in a spa. If a seam does go, a racesuit is usually repairable — we run a racesuit repair service in-store rather than writing the suit off.

Making any swimsuit last longer

  • Rinse in cold fresh water immediately after every swim — before the chlorine dries into the fibres. This single habit makes the biggest difference.
  • Never wring it out. Squeeze gently, or roll it in a towel to press the water out.
  • Dry flat, in the shade. Direct sun fades colour and heat damages elastic.
  • Rotate two suits if you swim more than three times a week.
  • Stay out of spas and hot tubs. Hot, heavily chlorinated water is the fastest way to ruin swimwear.
  • No dryer, no fabric softener — and no washing machine unless the brand allows it; Zoggs rates its Ecolast™ fabrics as machine washable.
  • Mind the concrete. Sitting on rough pool edges abrades the seat of a suit more than swimming ever will.

Frequently asked questions

What is the most chlorine resistant swimwear fabric?
100% polyester and PBT polyester are the most chlorine resistant swimwear fabrics. Because they contain no elastane, there is nothing for chlorine to break down, so they hold their shape and colour far longer than conventional blends. Speedo Endurance+, Funkita C-Infinity, Arena MaxLife Eco and Zoggs Aqualast are all polyester-based fabrics of this kind.

Is polyester or elastane better for swimming?
It depends on how often you swim. Polyester is better for regular pool training because it resists chlorine damage. Elastane and Lycra blends feel softer and fit more snugly when new, which suits beach swimming and occasional pool use, but they degrade quickly with frequent chlorine exposure.

What does PBT mean in swimwear?
PBT is a textured polyester yarn with natural stretch built into the fibre itself, rather than relying on added elastane. This gives swimwear four-way stretch and chlorine resistance at the same time, which is why PBT is common in training and racing suits.

What is the difference between Zoggs Aqualast, Ecolast and Elastomax?
Aqualast™ is Zoggs' 100% chlorine proof fabric with a lifetime fabric guarantee, used mainly in the learn-to-swim and toddler range. Ecolast™ and Ecolast+™ are recycled fabrics made from post-consumer plastic bottles, also covered by the Lifetime Guarantee, with Ecolast+ adding around four times the compression of generic swimwear fabric; composition varies by garment. Elastomax™ is 80% nylon and 20% elastane, an ultra-soft chlorine-resistant fabric rated for up to 120 pool hours and used in the modesty suit range. All are UPF 50+.

Can a chlorine-resistant fabric contain elastane?
Yes. Some fabrics marketed as chlorine resistant do contain elastane and achieve their durability through fibre treatment and construction rather than by eliminating it — Zoggs Elastomax™ at 80% nylon / 20% elastane is one example. They are softer than pure polyester and still far more durable than ordinary swimwear, but generally not as long-lived as a 100% polyester or polyester-PBT suit. Where a brand publishes a pool-hours rating, that is the most useful figure for comparison.

How long should a training swimsuit last?
A chlorine-resistant polyester suit worn four to six times a week will typically last a full season or longer with proper care. A standard elastane-blend suit under the same conditions may start losing shape within two to three months.

Does chlorine resistant mean the swimsuit lasts forever?
No. Chlorine resistant means the fabric resists the chemical breakdown that chlorine causes to elastane. The suit will still wear out eventually through abrasion, UV exposure and general use — it just takes far longer.

Do you sell swimwear fabric by the metre?
No — Swimwear Shack sells finished swimwear rather than fabric by the metre. If you're looking for material to sew with, a specialist fabric retailer is the right place. If you're trying to work out which fabric your next swimsuit should be made from, this guide and our team can help.

Can I get advice in person?
Yes. Our Woolloongabba store in Brisbane is staffed by people who swim, and we're happy to talk through fabric, fit and sizing face to face.

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