Labels like "80% polyamide, 20% elastane" actually tell you how a swimsuit will fit, how long it will last, and how it will feel. This guide teaches you how to read those numbers.
Elastane (Lycra, Spandex)
All three are names for the same fibre. Lycra is a brand, spandex is the American term, and elastane is the European one. So "contains Lycra" simply means quality elastane has been used.
Elastane is what gives fabric its stretch. The higher the percentage, the better the suit hugs the body and holds its shape. The ideal range for swimwear is 15–25%. Below 10% won't hold well; above 30% can feel unnecessarily tight and warm.
Polyamide (Nylon)
This forms the main body of most swimsuits. It's soft, quick-drying, and durable. It has a softer hand-feel than polyester, which is why it's preferred in luxury swimwear.
Polyamide also holds colour well — it fades more slowly in the sun than polyester. Its drawback is slightly lower chlorine resistance, so rinsing matters even more with heavy pool use.
Polyester
The most chlorine-resistant fibre, which is why it's common in training swimwear. But it doesn't feel as soft as polyamide and dries more slowly. For everyday and beach wear, polyamide is generally more comfortable.
Metallic Thread
A decorative fibre that creates a shimmering finish. It adds shine but contributes nothing to stretch — which makes a sufficient elastane percentage even more important in metallic pieces. These fabrics are also more delicate; friction against rough surfaces dulls the shine over time.
Why Lining Matters
It doesn't appear on the label, but it makes a big difference. A good lining does three things: prevents the fabric from becoming sheer when wet, supports the shape, and softens the surface against the skin. Unlined or partially lined suits look cheap and can behave unpredictably in water.
How to Read a Label
In short, look for: a polyamide-based body + 15–25% elastane + full lining. If all three are there, you're looking at a well-made fabric.
You'll find the fabric composition for every Rio Swim piece under the "Details" tab on each product page. Explore the Maré Alta collection or our new arrivals.