How to Wash Swimwear
Rinse immediately in cold water after every swim. This is the most important step — removing chlorine or salt before it dries in the fabric extends swimwear life significantly.
What Damages Swimwear
Swimwear is made from a nylon or polyester base fabric blended with 15–30% elastane (also sold as Lycra or spandex) — the synthetic polymer that gives swimwear its stretch and shape retention. Elastane is a polyurethane-based fibre that is vulnerable to three main stressors encountered during swimming. First, chlorine in pool water: chlorine is a powerful oxidising agent that breaks down the chemical bonds in polyurethane elastane. The degradation is not immediate — it accumulates over exposure time. A swimsuit left in chlorinated water for extended periods degrades faster than one rinsed immediately. Second, UV radiation: prolonged sun exposure accelerates elastane degradation through UV-induced oxidation, which is why swimwear worn on sunny pool decks fades and loses elasticity faster than swimwear used only indoors. Third, salt water: sea salt is less chemically aggressive than chlorine but can crystallise in fabric fibres if left to dry, which abrades the fibres over time and dulls colour. The combination of heat (hot car, bag, tumble dryer) and elastane degradation is immediately destructive — a single tumble dry cycle can compromise the elasticity of swimwear fabric. Heat accelerates all the chemical degradation processes.
How to Wash Swimwear
Rinse in cold water immediately after swimming
This is the single most important step. Rinse the swimwear under cold running water for 30–60 seconds while still at the pool, beach, or as soon as you get home. This removes chlorine, salt, and sunscreen before they have time to penetrate deeply into the fabric and begin degrading the elastane. Do not leave a wet swimsuit in a plastic bag or hot car — chlorine and heat together accelerate degradation significantly.
Hand wash in cool water with a gentle or swimwear-specific detergent
Fill a basin with cool water (20–25°C maximum). Add a small amount of gentle detergent — Woolite, Nikwax Tech Wash (designed for technical fabrics), a dedicated swimwear cleaner, or a small amount of mild shampoo. Submerge the swimwear and gently agitate by squeezing and releasing — do not rub, twist, or scrub. Leave to soak for 5–10 minutes, then rinse thoroughly with cool water.
Remove excess water by pressing gently — never wring
Gently press the swimwear against the side of the basin or between your hands to squeeze out water. Never wring or twist — this mechanically stretches and damages the elastane fibres while they are in a vulnerable wet state. Roll briefly in a clean dry towel and press to absorb moisture.
Dry flat or hang carefully in shade
Lay the swimwear flat on a clean dry surface or a mesh drying rack. Reshape to original dimensions. Avoid direct sunlight for drying — UV exposure while wet accelerates colour fading and elastane degradation. If hanging, use the widest section (the waistband or shoulder straps) rather than a narrow hook point, which can leave stretch marks.
Store dry in a cool, ventilated place
Never store a damp swimsuit folded in a tight bag — mould and mildew can develop within 24 hours, and the damp + enclosed environment continues the chlorine degradation process. Store fully dry, preferably flat or loosely folded in a breathable bag.
Stressors and How to Prevent Them
Chlorine (pool water)
Breaks down polyurethane bonds in elastane — progressive loss of stretch and shape retention. Coloured suits may fade.
Prevention: Rinse immediately after pool use. Do not leave wet swimwear in a bag. Rinse before entering the pool too — a saturated fabric absorbs less chlorine.
UV radiation
Accelerates elastane oxidation. Fades dyes. Weakens fabric over time — especially for swimwear used on sunny pool decks.
Prevention: Dry in shade. Do not hang in direct sun. Rinse sunscreen off the suit before drying.
Sunscreen / SPF products
Many sunscreen formulations stain swimwear — avobenzone causes orange discolouration with pool chlorine. Oily SPF products coat fibres and attract dirt.
Prevention: Apply sunscreen 15–20 minutes before putting on swimwear and allow it to absorb into skin. Rinse swimwear after beach use to remove sunscreen residue.
Heat (tumble dryer, hot car, bag in sun)
Single most destructive factor. Heat accelerates all chemical degradation and directly damages elastane polymer chains. One hot tumble dry can permanently alter the stretch of swimwear.
Prevention: Never tumble dry. Do not leave in a hot car or plastic bag. Air dry in shade.
Machine washing agitation
The elastane fibres tangle and strain under mechanical agitation, gradually reducing stretch retention over repeated cycles.
Prevention: Hand wash only. If machine washing is unavoidable: cold water, mesh bag, delicates cycle with low spin. Still not recommended for regular use.
Salt water
Salt crystals form in the fabric as it dries, abrading fibres and dulling colour. Less immediately damaging than chlorine but cumulative.
Prevention: Rinse immediately in cold fresh water after ocean swimming.
Rotate Two Swimsuits for Daily Swimmers
If you swim regularly — daily or multiple times per week — a single swimsuit will wear out significantly faster than if you rotate between two. Elastane needs 24–48 hours to fully recover its stretch after being wet and compressed. Using the same swimsuit every day without rest time means the elastane never fully recovers its shape, accelerating loss of fit. Two suits in rotation, each fully dried before re-use, will outlast a single suit used daily by 2–3× in terms of total lifespan.
Sunscreen Stains (Orange Marks)
Avobenzone — a common chemical UV filter — reacts with iron and minerals in pool water to form orange or brown stains on light-coloured swimwear. This is different from a fabric dye problem. Treatment: rinse the swimsuit thoroughly before the stain dries. For existing avobenzone-iron stains, apply citric acid (lemon juice or citric acid powder dissolved in water) to the stained area — citric acid dissolves the iron-avobenzone compound. Rinse thoroughly. Machine wash if the label allows. Mineral (physical) sunscreens (zinc oxide, titanium dioxide) do not cause this reaction and are safer for light-coloured swimwear.
What to Avoid
Tumble drying
Destroys elastane in a single cycle. Heat accelerates the chemical breakdown of polyurethane bonds. Never use the dryer for swimwear.
Leaving in a bag or hot car after swimming
Enclosed heat + residual chlorine creates accelerated elastane degradation. Rinse and hang to air as soon as possible after swimming.
Wringing or twisting to remove water
Mechanically stresses elastane fibres while wet and weakened, causing stretch marks and permanent deformation.
Machine washing regularly
Agitation from the drum stresses elastane. If you must machine wash, use a mesh bag, cold water, the most gentle cycle available, and minimum spin speed.
Washing with hot or warm water
Heat accelerates degradation. Cold water (20–25°C) is the maximum safe temperature for swimwear — even at the rinse stage.
Fabric softener
Fabric softener coats synthetic fibres with a waxy film that reduces their moisture-wicking and stretch properties. Never use on swimwear.
Drying in direct sunlight
UV plus heat from sun-drying fades colour and accelerates elastane degradation. Dry in shade.
FAQ
Can you machine wash swimwear?
Not recommended. Machine washing agitation stresses the elastane fibres that give swimwear its stretch. Cold hand wash is significantly safer and extends the life of the swimsuit. If you must use a machine, use a mesh bag, cold water only (30°C maximum), the most gentle cycle available, and do not tumble dry. For regular swimmers, hand washing is the only sensible approach.
How do you get chlorine smell out of a swimsuit?
Rinse immediately in cold water after swimming — this removes the chlorine before it bonds to the fabric. For an existing chlorine smell: soak the swimsuit in a solution of 1 tablespoon white vinegar per litre of cold water for 30 minutes, then hand wash with gentle detergent and rinse thoroughly. The vinegar neutralises residual chlorine compounds. Alternatively, a swimwear-specific wash (Nikwax, Speedo Swimwear Cleaner) is formulated for this.
How often should you wash a swimsuit?
After every swim — but a rinse in cold water is sufficient for many uses; a full hand wash every 2–3 uses is usually adequate for pool swimming. For ocean swimming or if the suit has absorbed sunscreen, a full hand wash after every use is recommended. The key is the immediate cold water rinse after every swim, even if a full wash follows later.
Why does my swimsuit lose its shape so quickly?
Shape loss in swimwear is primarily elastane degradation from: (1) chlorine or salt not rinsed out immediately; (2) heat — tumble drying, hot drying areas, or storing in a hot bag; (3) not allowing the swimsuit to fully dry and recover between uses (elastane needs 24–48 hours to regain shape). Using the same swimsuit daily without rest, and drying it in direct sunlight, are the most common accelerators of shape loss.
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