Nylon vs. Polyester Spandex: Which Is Better for Your Project?

If you’ve spent time shopping for swimwear fabric, you’ve seen both nylon spandex and polyester spandex. They look similar in photos, both stretch four ways, and they’re often similarly priced. So what’s actually different — and does it matter for your project?

The short answer: yes, it matters — especially for swimwear used in pools. Here’s the full breakdown so you can make the right choice every time.

At a Glance: Key Differences

Chlorine Resistance: Nylon Wins Clearly

This is the most practically important difference for anyone making swimwear that will be used in a chlorinated pool. Chlorine degrades synthetic fibers over time — but it attacks polyester much more aggressively than nylon.

In a competitive swimming context, where a suit might see 10–15 hours of pool use per week during a season, the difference between nylon and polyester is the difference between a suit that lasts a full season and one that loses its shape and elasticity by mid-season. This is why competitive swimwear — from club swim teams to Olympic racing suits — is almost universally nylon spandex.

The practical rule: If your swimwear is going in a chlorinated pool regularly, choose nylon spandex every time. If it’s primarily for beach or outdoor use where chlorine is minimal, polyester spandex is a reasonable choice.

UV Resistance: Polyester Has the Edge

Polyester is more naturally UV-resistant than nylon — it degrades more slowly under prolonged sun exposure. This matters most for outdoor activewear and swimwear worn in sunny conditions (beach, outdoor pools, paddleboarding, running outdoors).

If UV protection is your primary concern, polyester spandex or specialty nylon like Supplex Spandex — which has a UPF 50+ rating — are better choices than standard Milliskin nylon.

Softness: Nylon Feels Better Against Skin

Nylon fiber has a naturally higher luster and a softer hand than polyester. Against skin, nylon spandex typically feels more comfortable — particularly noticeable in garments worn tight against the body for extended periods: swimwear, leotards, activewear.

This difference is most pronounced in lower-quality fabrics. High-quality polyester spandex can feel quite comparable to standard nylon — but premium nylon like Supplex Spandex, which is processed to have a cotton-like feel, is in a different category entirely.

Color Vibrancy: Nylon Accepts Dye More Deeply

Nylon has a naturally higher dye uptake than polyester — colors go in more deeply and come out more vibrantly and consistently. For color-critical applications like competition dance where exact color matching matters, nylon spandex is the more reliable choice.

For fashion applications where the print or color is less critical, polyester performs excellently — particularly for sublimation printing, where polyester’s dye chemistry is actually superior to nylon.

Cost: Polyester Is Generally Less Expensive

Polyester fiber costs less to produce than nylon, and that difference carries through to finished fabric pricing. For budget-conscious projects where chlorine resistance and premium softness aren’t requirements — casual fashion, non-pool activewear, costume applications — polyester spandex is a legitimate economical choice.

When to Choose Nylon Spandex

• Swimwear for chlorinated pools (any frequency of use)
• Competitive dance costumes and gymnastics leotards
• Figure skating and ice dance costumes
• Premium activewear where softness and durability matter
• Any application where color accuracy and vibrancy are important
• Garments worn frequently for extended periods against skin

Shop nylon spandex: Milliskin Matte · Milliskin Shiny · Supplex Spandex

When to Choose Polyester Spandex

• Fashion garments and casual activewear that won’t see chlorine exposure
• Printed spandex where the design is the primary feature
• Budget-conscious projects where performance differences aren’t critical
• Beach and outdoor swimwear used primarily in non-chlorinated environments
• Projects where UV resistance is prioritized over chlorine resistance

Shop polyester spandex: Printed Spandex — our printed collection uses polyester spandex bases, which hold sublimation printing with excellent color accuracy.

The Bottom Line

For most performance applications — swimwear, dancewear, activewear — nylon spandex is the better choice. The chlorine resistance, softness, and color retention advantages are real and meaningful. For fashion, casual wear, and printed designs, polyester spandex is excellent and often more economical. When in doubt, request free samples of both and compare them side by side in person.

Related: What Is Milliskin Fabric? | Fabric Yardage Guide. Shop Nylon Spandex and Athletic Mesh.

For authoritative fabric care standards, see the .