Quick answer: For chlorine resistance, choose either a polyester/PBT swim knit (its stretch is mechanical, so it barely relies on spandex and holds up for months in a pool) or a nylon/spandex fabric made with a chlorine-resistant spandex grade such as Lycra XTRA LIFE or creora HighClo. Look for 4-way stretch and a weight around 170–230 GSM. (New to the terms? See our spandex glossary.)

Why chlorine matters

Chlorine, plus sunscreen and body oils, slowly breaks down standard spandex (elastane). As the elastane degrades, the suit loses recovery and starts to sag, bag and go see-through. Chlorine-resistant fabric is built to slow that breakdown so the suit keeps its fit far longer.

Best fabric types

Polyester/PBT blends are the most chlorine-resistant. PBT gives mechanical (textured) stretch, so the fabric doesn’t depend on spandex for its give — ideal for training suits and heavy pool use. The hand is firmer and very shape-stable. Nylon/spandex with chlorine-resistant spandex (18–25% elastane, XTRA LIFE or HighClo grade) keeps the soft, smooth feel most people prefer for fashion and beach swimwear while resisting breakdown better than ordinary nylon/spandex.

What to look for

Fiber content (polyester/PBT for max durability, or nylon with a named chlorine-resistant spandex); 4-way stretch with strong recovery; warp-knit tricot construction, which resists running and sagging; a weight of 170–230 GSM for support and opacity; and a UPF 50+ rating, which also signals the fibers hold up in sun.

Care to make it last

Rinse in cool fresh water right after swimming, hand-wash with mild detergent, never wring or tumble dry, and lay flat out of direct sun. Rotate suits and avoid hot tubs when you can — heat plus chlorine is what shortens elastane life fastest.

Shopping by the yard? Compare options in our swimwear vs dancewear vs activewear guide, browse fabric for swimwear, or request a free sample first.

What makes swimwear fabric chlorine-resistant?

Chlorine-resistant swim fabrics use polyester or PBT blends that hold up to pool chemistry far longer than standard nylon spandex.

Will chlorine-resistant fabric still stretch?

Yes. Quality chlorine-resistant knits keep strong 4-way stretch and shape retention.

Where can I buy chlorine-resistant swimwear fabric by the yard?

Stretch House sells swimwear and chlorine-resistant knits by the yard at stretchhouse.com, with free samples and worldwide shipping from New York since 2004.

Frequently Asked Questions

What makes swimwear fabric chlorine resistant?

Polyester and PBT blends resist chlorine far better than standard nylon-spandex, keeping shape and color through pool use.

Is nylon spandex okay for swimwear?

It works well for fashion and occasional swim use, but heavy chlorine exposure degrades the spandex faster than poly blends.

How do I make swimwear last longer?

Rinse in cool water after every swim, avoid wringing, keep it out of the dryer, and rotate between suits.

What stretch do I need for swimwear?

Look for strong four-way stretch with good recovery so the suit hugs the body and springs back after wear.