How to Hand-Wash Your Swimsuit (and When Machine-Wash Is OK)
By the Bikini Uni team. Updated June 2026.
The actual routine — five minutes, mostly cold water — and a clear rule for when the machine is fine.
Why hand-washing wins (most of the time)
A swimsuit isn't a t-shirt. The structural pieces of a suit — straps, band elastic, leg openings, any cup or bra-style support — are held in shape by elastic fibers spun in with the main fabric. Heat softens those fibers. Mechanical agitation stretches them. Detergent residue stiffens them. A washing machine does all three.
That doesn't mean machine wash is forbidden. It means hand-wash is the default and the machine is a controlled exception. We covered the broader "why swimsuits fail" question in How to Make a Swimsuit Last More Than One Season; this post is the specific how-to.
The hand-wash routine (five minutes)
Start the moment you're out of the pool or ocean if you can. Cooler the water, sooner the rinse, longer the suit lives.
1. Cool rinse, no soap. Under the bathroom sink or shower head, rinse the suit in cool — not cold, not warm — running water for thirty to sixty seconds. The point is to flush out chlorine, salt, sunscreen, and sand before they have a chance to chemically bond with the elastic. This step alone is the single biggest extender of a swimsuit's life.
2. Fill a basin with cool water and a small amount of detergent. A bathroom sink, a small bucket, or a clean washing basin. About a teaspoon of fragrance-free, dye-free liquid detergent per gallon of water. "Gentle," "delicate," or "wool-and-silk" labels are right; "everyday laundry" with brighteners and enzymes is wrong. Avoid bleach of any kind, including the "colour-safe" bleaches.
3. Submerge and press. Push the suit under and gently press the water through it with flat hands. Do this for two to three minutes. No scrubbing, no twisting, no rubbing fabric against itself. Just press, release, press.
4. Rinse twice. Drain the soapy water, refill the basin with clean cool water, press the suit through it the same way. Drain again, refill, repeat once more. Detergent residue is one of the things that breaks down elastic over time; the second rinse is what removes it.
5. Press dry, don't wring. Lay the suit flat on a clean towel, fold the towel over it like a sandwich, and press down with flat palms to push the water into the towel. If it's still soaked, repeat with a dry section of the towel. Do not twist the suit. Do not wring it. Twisting is the single fastest way to break the band elastic.
6. Air-dry flat, in shade. Lay the suit flat on a dry towel or a clean mesh drying rack, somewhere out of direct sunlight. UV does to suit fabric what it does to a car interior — it bleaches color and degrades elastic. Indoor air-dry takes four to twelve hours depending on humidity. Don't hang dry from straps; the weight of the wet fabric pulls the straps out of shape.
That's the routine. Five minutes of active work plus the dry time.
When machine wash is actually fine
Real talk: most people will not hand-wash a swimsuit every time. Here's the rule for machine wash that won't destroy the suit:
Cycle: Delicates, hand-wash, or "wool" cycle. Not regular, not heavy.
Water: Cold only. Warm or hot will kill the elastic faster than any other single mistake.
Bag: Mesh laundry bag (the kind sold for bras and lingerie). Zip it. This prevents the suit from snagging on other items, the drum, or the agitator.
Detergent: Same gentle, fragrance-free liquid you'd use by hand. Half a normal dose. No fabric softener — softener coats fibers and makes them retain water and break down faster.
Other items: Wash with other delicates — bras, light layers, silk — not with towels, jeans, or anything heavy. Towels especially are bad partners because the wet weight pulls everything around.
Dryer: NEVER. No exceptions. Even the "no heat" tumble setting is hard on elastic. Always air-dry flat per the hand-wash routine above.
Used correctly, machine wash will be most of the way as gentle as hand-wash. The cost is that you can't see how the fabric is moving, so a small snag or stress point you'd notice while hand-washing might progress further before you catch it.
The three things that actually shorten a swimsuit's life
Forget product-specific advice. The three causes of swimsuit failure, in order:
1. Heat. Hot water, the dryer, leaving a wet suit baking on a car seat in the sun. Heat softens elastic in a way it does not recover from. Cool water and shade are the rule.
2. Chlorine left sitting in the fabric. Chlorine is a halogen — it chemically reacts with elastic over hours and days. The damage is roughly proportional to how long the chlorine sits in the suit, not how much chlorine was in the pool. Rinsing within thirty minutes of swimming cuts chlorine damage by more than half.
3. Mechanical stress on elastic. Twisting, wringing, agitating in a regular wash cycle, hanging by the straps to dry. Each of these mechanically deforms the elastic. The elastic recovers from one or two stretches; ten thousand stretches over a season add up.
If you only do three things, do these: rinse in cool water immediately after swimming, never use the dryer, never twist or wring the fabric. The full routine above is the version that maximizes lifespan; this short version is the version that prevents the worst failures.
Between-swim care
Care happens between washes too. A wet suit balled up in a beach bag for two hours is the worst-case ambient environment — warm, dark, damp, with detergent and sweat already in the fabric. Some quick rules:
Rinse before, not just after. Pre-soaking a suit in plain cool water before you swim makes the fabric absorb water rather than pool chemicals. This reduces total chlorine uptake by a real margin.
Don't bag wet. If you can't rinse right after a swim, at least lay the suit flat in your bag rather than balling it up. A wet-bag with a wet-side and dry-side is worth the seven dollars.
Rotate suits. If you swim multiple times a week, two suits in rotation last more than twice as long as one suit used twice as often. Elastic recovery happens between uses.
Storage between uses
For a suit you'll use again this week: flat on a shelf, dry, not folded into a permanent crease. For a suit going into off-season storage: clean, completely dry, folded loosely with tissue paper inside the cups (if any) to maintain shape. Plastic bags are bad — they trap residual moisture; cotton or muslin storage bags are right. Storage temperature should be moderate (don't store in an unheated attic or a hot garage).
When to repair vs replace
A swimsuit at the end of its life shows three signs: elastic that no longer recovers (you stretch it, it stays stretched), fabric that has gone dull and crinkly even when wet, and pilling on high-friction areas like the inside band. Two of three usually means it's done. One of three — especially elastic on a single strap — is often a simple repair: a tailor can replace a stretched strap on most cuts for $15-25. Fabric and elastic-throughout failure is not worth repairing.
Putting it together
Hand-wash is five minutes of cool water, gentle soap, no twisting, flat dry in shade. Machine wash is fine occasionally if you commit to cold water, a mesh bag, a delicates cycle, half-dose detergent, and never the dryer. The three big killers — heat, sitting chlorine, mechanical stress — are independent of which method you choose; avoid all three and most suits hold for two to three seasons.
This is the kind of routine where the small habits matter more than the big rituals. The rinse-immediately step is worth more than the most careful weekly hand-wash. The never-the-dryer rule is worth more than picking the perfect detergent. Start with those two and the rest is refinement.
The reason it matters: any swimwear is an investment, and the math only works if the piece lasts. Our handmade tier carries an explicit premium — we explain why here. Cool water, no heat, no twisting. That's the whole guide.
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