How to choose fabric for a bespoke swimsuit
By the Elk Pegasus studio,
What the numbers on a fabric label actually tell you, and what they leave out
Fabric choice is the decision most clients find hardest. The options are wider than they expect, the terminology is unfamiliar, and the stakes feel high because the fabric is the most visible part of the finished piece. This guide covers the main categories of swimwear fabric, what the specifications mean in practice, and how to think about the choice before a first consultation.
Lycra content and what it means for fit
Swimwear fabric is almost always a blend of polyester and elastane, with the elastane content determining how much stretch and recovery the fabric has. A fabric with 18 to 22 percent elastane will stretch significantly and return to its original shape reliably. Below 15 percent, the fabric may stretch but recover more slowly, which means it can lose its shape over a season of regular use.
The weight of the fabric, measured in grams per square metre, affects how the garment sits on the body. Lighter fabrics, around 180 to 200 gsm, drape softly and move easily. Heavier fabrics, 220 gsm and above, hold their shape more firmly and are better suited to structured cuts like a bandeau or a high-neck one-piece.
Chlorine resistance and UV protection
If a swimsuit will be worn primarily in a pool rather than the sea, chlorine resistance matters more than most clients expect. Chlorine degrades elastane fibres over time, causing the fabric to lose its stretch and, eventually, to become translucent. Fabrics described as chlorine-resistant use a modified elastane fibre that degrades more slowly. The difference in lifespan between a standard and a chlorine-resistant fabric, with regular pool use, is significant.
UV protection is rated using the UPF scale. A fabric rated UPF 50+ blocks more than 98 percent of UV radiation. Most quality swimwear fabrics achieve this rating, but it is worth confirming, particularly for pieces intended for extended outdoor use in strong sun.
Texture and finish: matte, ribbed, and sheen
The surface finish of a fabric changes how it reads in different lights and how it photographs. Matte fabrics absorb light and tend to look more understated. Ribbed fabrics have a tactile texture that adds visual interest without pattern. Fabrics with a slight sheen catch light and can read as more formal or evening-appropriate.
There is no hierarchy among these finishes; the right choice depends on the cut and the context in which the piece will be worn. A ribbed fabric works well on a simple one-piece where the texture carries the design. A matte fabric suits a bikini with interesting hardware or an unusual cut, where the fabric is a background rather than a feature.
How we approach fabric selection at the studio
At Elk Pegasus, the base fabrics in the studio selection are Italian-made stretch fabrics. We handle and test each fabric before adding it to the studio selection, checking stretch recovery, colour fastness, and how the fabric behaves when cut on the bias. Clients who visit the studio can handle the fabrics directly, which is the most reliable way to make a choice.
For remote clients, we describe each fabric in detail during the video consultation and can post small swatches on request. The current collection page shows the fabrics available this season.
If you are unsure which fabric suits the piece you have in mind, bring the question to the first consultation. Handling the fabric in person usually resolves the uncertainty quickly.