What Are Swim Shorts Made Of? A Guide to the Best Swimwear Fabrics

What are swim shorts made of? A breakdown of common fabric

When it comes to standard swimwear, it’s usually made from run-of-the-mill nylon or polyester—both synthetic fibres. Technically, these fabrics do the job, but there’s a catch.

Most fast-fashion swim shorts contain minimal elastane. Translation? Less stretch, poor shape retention, and a higher chance of that all-too-common sag after just a few wears. 

By mid-summer, those bargain bathers have faded, and the fabric is already pilling. Not to mention, sustainability is often an afterthought (if it’s considered at all).

What makes Sheila fabric different

We knew there had to be a better way. That's why our swim shorts are crafted from premium materials that prioritise both performance and the planet:

• Main fabric: 75% Global Recycling Standard (GRS) certified recycled nylon, 25% elastane.
• Lining: 80% recycled nylon, 20% elastane.
• Certification: STANDARD 100 by OEKO-TEX for safety. More on that here.
• Sun protection: UPF 50+ rated (because Australian sun doesn't mess around, learn more here).

So, what do those percentages and certifications actually mean for you?

How elastane improves the fit of swim shorts

It's simple: more elastane means better fit and flexibility. While cheaper options might include just 5-10% elastane, our 25% blend gives you that perfect balance of structure and stretch. It holds you in without restricting movement, so no chafing or pinching in sight.

The recycled nylon we use is also a win-win. It’s gentler on the environment and performs better in water. It feels softer against skin, maintains its shape swim after swim, and dries quickly when you're ready to move from beach to brunch.

Swimwear that lasts: Colour, shape & sun protection

The hard truth about fast fashion: it’s not designed to last. It's designed to be replaced.

Sheila's fabric tells a different story. Our recycled nylon is resistant to salt, sun, and sagging. It holds its shape and colour far longer than standard swimwear materials.

That said, even the highest-quality fabrics have their kryptonite. For our swimmers, it's chlorine, known to gradually fade bold colours over time. If you're a regular pool-goer, we recommend our Black Sand colourway for maximum longevity. Darker shades simply handle chemical exposure better, keeping their tone swim after swim.

What’s the most sustainable fabric for swim shorts?

Beyond performance and durability, there's something powerful about wearing swimwear that aligns with your values. Our recycled nylon is crafted from discarded waste (like fishing nets, carpets, and plastics) through a meticulous process of sorting, cleaning, and regenerating. These materials are given new life, turning potential ocean pollution into something beautiful and meeting the Global Recycling Standard along the way.