How to Spot a Quality Swimsuit: Fabric, Lycra Content and Label Reading Guide (2026)

Of two swimsuits that look identical, one keeps its shape for three seasons while the other sags, fades and goes baggy after the first holiday. The difference is not in the design; it is hidden in the fabric, the Lycra content and the inner construction. In this guide we explain, step by step, how to tell whether a swimsuit is well made before you buy it.

The short answer: how do you spot a quality swimsuit?

A quality swimsuit has these six features together: (1) a fabric based mainly on polyamide (nylon) rather than polyester, (2) an elastane/LYCRA® content of at least 15%, ideally above 20%, (3) full lining that does not turn see-through when wet, (4) a dense knit that does not go white when stretched, (5) test-certified hardware that does not bleed colour or tarnish, (6) double-stitched, overlocked edges that keep their stretch.

1. Fabric: polyamide or polyester?

Swimwear fabrics are made from two main fibres, and the two behave completely differently.

Polyamide (nylon)

Softer and silkier, it fits the body better. It is highly elastic, holds little water when wet and dries quickly. Almost all premium swimsuits are polyamide-based. The downside: good polyamide fabric is expensive, so you rarely find it in cheap pieces.

Polyester

Cheaper, more resistant to chlorine and holds its colour longer. It is a sensible choice for pool and competitive swimming costumes. However, it has a stiffer hand, does not fit the body as well as polyamide and can feel thick.

MOVOM collections primarily use Italian Carvico fabric and polyamide blends containing LYCRA®; for example, the PAVELLE Underwire Shell Bikini is made from a blend of 85% recycled polyamide and 15% elastane.

2. Lycra (elastane) content: the most important number on the label

Elastane, commonly known as Lycra, determines how well a swimsuit stretches and springs back into shape. The higher the percentage, the better the swimsuit hugs the body and the longer it stays without sagging.

• 5–10% elastane: Low end. It stretches out in the first season and loses its shape by the second.
• 12–15% elastane: An acceptable mid-range. It does the job for everyday wear.
• 18–25% elastane: The premium range. It hugs and shapes the body and stays put during active wear.

If the label says LYCRA® rather than just "elastane", that is a good sign: LYCRA®-branded elastane is noticeably more resistant to chlorine, sunscreen and salt water than generic elastane. The KAORA Strapless Ring Bikini and the SIREN Bustier Swimsuit sit in this top tier with a blend of 77% polyamide and 23% LYCRA®.

3. Fabric comparison table

4. Lining and inner construction: the quality you cannot see

The inside of a swimsuit matters as much as the outside. What to check:

• Full lining: A quality swimsuit is lined throughout. Half-lined or unlined pieces become see-through when wet. A printed inner lining is standard on MOVOM styles.
• Power mesh: This firm knit lining, used in corsetry and shapewear, smooths the body and stops strapless styles from slipping. The LEONE Strapless Belted Swimsuit is made with a power mesh inner lining; it is normal for it to feel snug the first time you wear it, and it soon adapts to your body.
• Removable pads: Sewn-in fixed padding creases in the wash and leaves permanent marks. Removable pads last longer and let you choose how much padding you want.
• Underwire: Concealed wires in the side seams provide bust support and shape. The wire tips should be neatly enclosed in the fabric; any digging in is a sign of poor workmanship.

5. Hardware, stitching and colourfastness

The first part of a swimsuit to fail is usually its metal hardware. Salt water and chlorine tarnish uncoated metals within a few wears and leave green-black stains on the fabric. Quality brands put their hardware through fastness tests — MOVOM hardware comes with an Azolab test report and shows high resistance to tarnishing and fading.

Look at the stitching too: if the edges are finished with a single row of straight stitching, the seam will burst when the fabric is stretched. Look for stretch overlock or twin-needle stitching.

6. Three quick tests you can do in store

1. The stretch test: Stretch the fabric in both directions. If it goes white, thins out or turns see-through, the knit is loose. If it does not snap straight back into shape when released, the elastane content is low.
2. The light test: Hold the fabric up to the light. If light passes through it noticeably, it will also turn see-through when wet.
3. The label test: If there is no composition label, or it only says "polyester", the brand most likely did not want to share the blend.

Styles that meet these criteria, with every size in stock

The styles below have sizes XS, S, M and L all in stock — each is made from a premium polyamide and LYCRA®/elastane blend, fully lined and fitted with removable pads.

LEONE Strapless Belted Swimsuit
Power mesh lining PAVELLE Underwire Shell Bikini
85% recycled polyamide KAORA Strapless Ring Bikini
23% LYCRA® BRIDA Underwire Shell Bikini
Underwire support KAELIS Bralette Bikini
Removable pads SALMA Underwire Bikini
Classic black

Keeping a quality swimsuit in top condition

Even the best fabric can be ruined in a single season by the wrong care. The basic rule: after the sea or pool, rinse your swimsuit in fresh water, hand wash it in cold water, roll it in a towel to remove moisture without wringing, and dry it flat in the shade. For detailed care steps, see our article Swimsuit Care: 7 Rules to Keep Your Swimsuit Like New for Years.

Once you have chosen the right fabric, the next step is the right size. MOVOM patterns run small compared with standard European sizes; before taking your measurements, we recommend reading our Swimsuit and Bikini Size Guide.

Frequently Asked Questions

What should the Lycra content of a swimsuit be?

The ideal range is 15–25%. Below 15%, a swimsuit does not hug the body enough and loses its shape after a few wears. Above 25%, it can become unnecessarily tight and difficult to put on.

Which is better, polyamide or polyester?

For the sea and everyday beach wear, polyamide is better: it is softer, fits better and dries quickly. For regular pool use and swim training, polyester makes more sense because it is more resistant to chlorine.

How many seasons does a swimsuit last?

A swimsuit made from a premium polyamide and LYCRA® blend can last 3–5 seasons with proper care. Budget pieces with low elastane content usually stretch out and lose their shape within a single season.

Why do swimsuits fade or yellow?

There are three main causes: chlorine, the oils and chemical filters in sunscreen, and UV light. The most practical way to protect against them is to rinse your swimsuit in fresh water as soon as you get out of the water, and to apply sunscreen a few minutes before putting your swimsuit on so it has time to absorb.

Is it worth buying an unlined swimsuit?

We do not recommend it. Lining does more than prevent sheerness; it gives the fabric structure, keeps you comfortable and helps the swimsuit hold its shape. Full lining is essential, especially on light-coloured swimsuits.

Should push-up pads be removable?

Yes. Removable pads do not lose their shape in the wash, speed up drying and let you opt for a more natural look whenever you like. For example, the MANU Bralette Bikini comes with removable push-up pads.

In summary

A quality swimsuit reveals itself not in the print you see but in the fabric you feel and the label you read. A polyamide-led blend, more than 15% LYCRA®, full lining, removable pads and test-certified hardware — a swimsuit with these five features may look a little more expensive in the first year, but its cost per season works out far lower. Explore the MOVOM swimsuit and bikini collection to find the fabric and fit that suit you.