How to Design Swimwear: Fabrics, Fit, and Construction
How to design swimwear — covering specialized fabrics, fit requirements, construction techniques, and compliance standards for swimwear production.
Swimwear fabric requirements
Swimwear fabric must perform in chlorinated pools, salt water, and direct sunlight. Standard fashion fabrics will fail quickly in these conditions.
- Nylon/spandex blend: Industry standard (typically 80/20 or 78/22 ratio)
- Chlorine resistance: Essential for any swimwear intended for pool use
- UV protection: UPF rating of 50+ for sun-protective swimwear
- 4-way stretch: Required for comfortable fit and movement
- Quick-dry: Fast moisture evaporation for comfort
- Shape retention: Must hold its shape after repeated stretching and washing
- Color fastness: Must resist fading from chlorine, salt water, and UV exposure
Fit and sizing challenges
Swimwear is among the most fit-sensitive garment categories. Body-conscious styles require precise grading and size-specific pattern adjustments. Every millimeter of cup depth, leg opening, and waistband placement affects comfort and coverage.
Size inclusivity is increasingly important in swimwear. If you plan to offer extended sizes, budget for additional fit testing with size-specific fit models rather than simply grading up from a base size.
Construction for swimwear
Swimwear construction uses specialized techniques:
- Flatlock seams: Standard for swimwear to prevent chafing
- Elastic application: Clear elastic or picot elastic at leg openings and necklines
- Lining: Front lining is standard, typically in power mesh or self-fabric
- Boning and underwire: For supported top styles, specify type and channel construction
- Gripper elastic: Inside waistbands and leg openings to prevent riding
Compliance and testing
Swimwear has specific compliance requirements including colorfastness testing (AATCC standards), stretch recovery testing, and care label requirements. If selling in the US, ensure your swimwear meets CPSC requirements. For children's swimwear, additional safety testing is required under CPSIA.