Your kid's swimsuit is slowly dissolving. Not in a dramatic, falling-apart way. In a quiet, invisible, fibre-by-fibre way that means the rashie you bought in October is baggy by January.
Here's why: chlorine reduces the tensile strength of Lycra and Spandex by up to 65.7% after 300 hours of exposure. That's the equivalent of swimming for an hour a day for a school year. And it's not just chlorine. Saltwater, sand, UV exposure, and the way you wash (and dry) swimwear all contribute to premature breakdown.
The good news? Most swimwear damage is preventable. A few simple habits can double or even triple the life of your kid's swimmers - saving you money, reducing waste, and keeping their gear performing the way it should.
Here's how.
Why Kids' Swimwear Breaks Down (The Science)
Understanding what's happening to the fabric helps you prevent it.
Chlorine: The Biggest Culprit
Pool chlorine is a powerful oxidiser. That's how it kills bacteria. But it also attacks the elastic fibres in swimwear - particularly elastane (also sold as Lycra or Spandex), which gives swimsuits their stretch.
What the research shows:- Elastane loses 65.7% of its tensile strength after 300 hours of chlorine exposure
- Colour fading begins within the first 50 hours of pool use
- UPF protection degrades after 30-50 washes, with chlorine accelerating the decline
- Chlorine breaks down swimwear roughly three times faster than saltwater
If your child swims in a chlorinated pool multiple times a week (squad training, lessons, weekend play), their swimwear is taking a real beating.
Saltwater: Gentler, But Not Harmless
Saltwater is less aggressive than chlorine, but it still causes damage over time. Salt crystals left in fabric act as tiny abrasives, weakening fibres with every wear. Saltwater also promotes bacterial growth if swimwear is left damp for too long.
Sand: The Hidden Shredder
Sand particles are essentially tiny rocks. When they get trapped in swimwear fabric (particularly in seams and lining), they cause abrasion every time your child moves. Over time, this weakens fibres and creates thinning spots - especially in high-friction areas like the seat and inner thighs.
UV Exposure: Fading and Fibre Damage
The same UV radiation that sunburns skin also degrades fabric. UV breaks down the molecular bonds in synthetic fibres, causing fading, brittleness, and loss of elasticity. Leaving swimwear to dry in direct sunlight accelerates this process significantly.
Heat: The Silent Killer
Tumble dryers, hot car boots, and hot water all damage elastane. Heat causes the elastic fibres to lose their memory - that "snap back" quality that keeps swimwear fitting snugly. Once elastane is heat-damaged, the stretch doesn't come back.
Care Guide by Swimwear Type
Different materials need different care. Here's what to do for each type of swimwear your kid probably owns.
Swimsuits, Rashies and One-Pieces (Nylon/Elastane Blend)
Most kids' swimwear is made from a nylon-elastane blend. This includes rashies, one-pieces, board shorts, and swim trunks.
After every swim:- Rinse immediately in cool, fresh water. Don't wait until you get home - a quick rinse at the pool or beach shower removes the majority of chlorine, salt, and sand
- Gently squeeze out excess water. Never wring or twist - it distorts the fabric and stresses the seams
- Lay flat to dry in the shade, or hang on a wide hanger (not a thin wire one that creates stretch marks). Never dry in direct sunlight
- Hand wash in cool water with a mild detergent (no fabric softener - ever)
- If using a machine, use a cold, gentle cycle inside a mesh laundry bag
- Fabric softener coats fibres and breaks down elastane. It's the single most common mistake parents make
- Avoid bleach, stain removers, and anything with optical brighteners
- Always store completely dry. Damp swimwear breeds bacteria and develops that musty smell
- Store flat or loosely folded - don't scrunch into a ball
- Keep away from rough surfaces like Velcro, zippers on other clothing, and pool bags with gritty interiors
Wetsuits (Neoprene)
If your child has a traditional neoprene wetsuit (from any brand), here's how to extend its life.
After every use:- Rinse thoroughly in cool, fresh water - inside and out
- Turn inside out and soak in a bucket of fresh water for 10-15 minutes to flush salt and chlorine from the neoprene cells
- Hang on a wide, padded hanger (a thick plastic one or a proper wetsuit hanger). Never use a wire hanger - it creates shoulder bumps that become permanent
- Dry in the shade. Direct sunlight degrades neoprene and causes it to become stiff and brittle
- Use a wetsuit-specific wash or a very mild soap. Regular detergent is too harsh for neoprene
- Never machine wash a wetsuit
- Never tumble dry a wetsuit
- Never iron a wetsuit (yes, people have tried)
- Hang on a wide hanger in a cool, ventilated space
- Never fold a wetsuit for storage - folding creates permanent creases in the neoprene
- Keep away from heat sources (hot water systems, heaters, sunny windows)
Wetsuits (Yulex Plant-Based Rubber)
Yulex natural rubber - like the material used in AVALY wetsuits - is cared for the same way as neoprene, with a few differences.
The good news: Yulex is naturally more resistant to UV degradation than petroleum-based neoprene, and it doesn't contain the same chemical plasticisers that break down over time. It also doesn't develop the "neoprene smell" as quickly. The same rules apply:- Rinse in cool fresh water after every use
- Dry in the shade on a wide hanger
- Never fold for storage
- Never machine wash or tumble dry
The Five Most Common Mistakes (And What to Do Instead)
| Mistake | Why It's Bad | What to Do Instead |
|---|---|---|
| Leaving wet swimwear in a bag | Breeds bacteria, causes odour, accelerates fabric breakdown | Rinse and hang to dry as soon as possible |
| Using fabric softener | Coats and degrades elastane fibres, reduces stretch | Use mild detergent only, or a swimwear-specific wash |
| Drying in direct sunlight | UV degrades fibres, fades colours, reduces UPF rating | Dry in the shade - always |
| Wringing out swimwear | Distorts fabric, stresses seams, stretches elastic | Gently squeeze or roll in a towel |
| Machine washing on hot | Heat destroys elastane's memory permanently | Cold gentle cycle only, inside a mesh bag |
Does UPF Protection Wear Out?
Yes. And this is the one most parents don't know about.
UPF (Ultraviolet Protection Factor) measures how much UV radiation a fabric blocks. A UPF 50+ rating means the fabric blocks over 98% of UV rays. But that rating applies to the garment when new.
What affects UPF over time:- Stretching: When fabric stretches (from wear or from loss of elasticity), the gaps between fibres widen, allowing more UV through
- Chlorine damage: Chemical breakdown of fibres reduces UV-blocking capacity
- Washing: UPF can degrade after 30-50 washes, depending on the fabric and care method
- UV exposure itself: Ironically, the UV that the fabric blocks also slowly degrades the fabric's ability to block UV
- Follow all the care guidelines above (especially rinse after chlorine and dry in shade)
- Replace swimwear that's lost its stretch - saggy fabric has lower UPF
- Choose tighter-weave fabrics and darker colours, which naturally block more UV
- Look for swimwear tested to the Australian standard (AS/NZS 4399) - it's the most rigorous UPF testing standard in the world
The Cost-Per-Wear Argument
Here's a practical way to think about it.
A $10 swimsuit from a fast fashion brand might last one summer season before it's faded, saggy, and functionally useless. If your child wears it 30 times, that's 33 cents per wear.
A $50-80 quality swimsuit, properly cared for, can last two to three seasons (or be passed down to a sibling). If it gets 100 wears, that's 50-80 cents per wear - but it also kept its UPF protection, its shape, and its colour for the entire time.
A well-made wetsuit that's properly cared for can last three to five years, or be passed through two or three kids. The cost-per-wear drops dramatically - and that's before you count the environmental benefit of keeping it out of landfill.
Over 220,000 tonnes of clothing end up in Australian landfill every year. Making swimwear last longer is one of the simplest ways to reduce your family's contribution to that number.Quick-Reference Care Cheat Sheet
Always:- Rinse in cool fresh water after every swim
- Dry in the shade
- Store completely dry
- Wash in cold water with mild detergent
- Use a mesh laundry bag for machine washing
- Use fabric softener
- Tumble dry
- Wring or twist
- Dry in direct sunlight
- Leave wet in a bag
- Fold a wetsuit for storage
- Use bleach or stain removers
- Sit on rough surfaces (concrete pool edges are murder on swimwear)
When to Replace Kids' Swimwear
Even with perfect care, swimwear doesn't last forever. Here's when it's time:
- Lost elasticity: The fabric doesn't snap back when stretched, or the swimsuit sags when wet
- Visible pilling or thinning: Especially in high-friction areas
- Permanent odour that persists after washing
- Faded colour (aesthetic, but also indicates fibre degradation)
- Seam damage that can't be repaired
- Wetsuit stiffness: Neoprene that's become rigid has lost its insulating properties
For kids who swim regularly (lessons, squad, beach weekends), expect to replace standard swimsuits every one to two seasons, and wetsuits every two to four years depending on care and growth spurts.
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Frequently Asked Questions
How do you make kids' swimwear last longer?
Rinse in cool fresh water immediately after every swim (pool or ocean), never use fabric softener, always dry in the shade, and wash in cold water with mild detergent. These four habits alone can double the lifespan of kids' swimwear. Chlorine is the biggest enemy - it reduces elastane strength by up to 65.7% over time, so rinsing it out quickly is the single most impactful thing you can do.
Can you put kids' swimwear in the washing machine?
Yes, but only on a cold, gentle cycle inside a mesh laundry bag. Never use hot water (it destroys elastane's stretch memory permanently), never use fabric softener (it coats and degrades elastic fibres), and never tumble dry. Hand washing in cool water is even better. Wetsuits should never go in a washing machine.
Does chlorine ruin swimwear?
Yes. Chlorine is a powerful oxidiser that breaks down the elastane (Lycra/Spandex) fibres that give swimwear its stretch. Research shows elastane loses up to 65.7% of its tensile strength after 300 hours of chlorine exposure. Rinsing swimwear in fresh water immediately after pool swimming is the most effective way to minimise damage.
Does UPF protection wear out on rashies?
Yes. UPF ratings apply to the garment when new, and protection can degrade after 30-50 washes, particularly if the garment has been exposed to chlorine, dried in direct sunlight, or has lost its stretch. Stretched or saggy fabric has wider gaps between fibres, allowing more UV through. Proper care maintains UPF protection for longer.
How do you care for a kids' wetsuit?
Rinse in cool fresh water after every use (inside and out), soak for 10-15 minutes to flush salt from the neoprene cells, and hang on a wide padded hanger in the shade to dry. Never fold a wetsuit for storage (it creates permanent creases), never machine wash, never tumble dry, and keep it away from direct sunlight and heat sources. Use a wetsuit-specific wash rather than regular detergent.
Is it worth buying expensive kids' swimwear?
When you calculate cost-per-wear, quality swimwear often works out cheaper than fast fashion alternatives. A $10 swimsuit lasting one season (30 wears) costs 33 cents per wear. A $50-80 quality swimsuit lasting two to three seasons (100+ wears) costs 50-80 cents per wear but maintains its UPF protection, shape, and colour throughout. Quality swimwear can also be passed down to siblings, further reducing cost and waste.