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UPF 50 Swimwear UV Protection Info

UPF Swimwear

The Ultraviolet Protection Factor (or “UPF”) rating measures the UV protection provided by a fabric. It is similar to the SPF rating used for sunscreens. Berry Jane™ rash guards, swim leggings and swimsuits rating ranges from UPF 30 to 50. A UPF 50 fabric allows 1/50th of UV radiation to pass through it, blocking 98% under the conditions measured. Typically, UPF 50 fabric is made of polyester and a darker color fabric.

UPF UV protection with clothes and swimwear

No clothing can completely block all UV rays. Protection depends on fabric construction, color, coverage, fit and condition. Wetting and stretching can reduce protection; darker or brighter colors generally offer more protection than lighter shades. Use clothing alongside sunscreen and other sun-protection measures.

What Influences Fabric UPF?

Fiber Content: Synthetics like polyester and nylon naturally absorb and scatter UV light better than untreated natural fibers like cotton. Cotton averages 5 UPF, while polyester often ranges 20–50.
Weave Density: Tightly woven or knitted constructions reduce the gaps between threads where light can pass.
Color and Dye: Darker and more saturated colors absorb more UV radiation than lighter shades. 

Wet & In-Water UPF FAQ

Can I wear Berry Jane™ rash guards in the water, and does UPF 50 still apply?

Our swim rash guards include styles intended for swimming and watersports. However, suitability for swimming is not a guarantee of unchanged UV protection when wet. UPF describes UV transmission through fabric under testing conditions. We do not provide a wet-state test report confirming UPF 50 for each style, color and degree of stretch, so do not assume the listed rating guarantees the same protection in water.

What do “damp” and “wet” mean for UV protection?

Here, “damp” means fabric moistened by sweat or splashes; “wet” means soaked fabric during or after swimming. These are everyday descriptions, not separate UPF ratings. The Skin Cancer Foundation advises that wetting or stretching clothing can reduce its protective ability. The amount of change cannot be determined from fabric color or fiber percentages alone.

Does the polyester/spandex fabric help?

Our UPF 50+ Performance Swim Rash Guard for Active Watersports, Retro Stripe lists 82% polyester and 18% spandex. Other styles use different blends, so check the individual product details. Dense fabric construction generally helps block UV, and polyester can be protective, but we have not verified a tight-weave specification or wet-state UPF result for this style here. The blend alone does not establish wet protection. Choose adequate coverage and avoid overstretching the garment.

How should I care for my swimwear?

Follow your garment’s care instructions. The 82% polyester/18% spandex performance style specifies cold delicate or gentle hand washing, no bleach, air/line drying and avoiding rough surfaces. Some other rash guards also specify rinsing after each use to remove salt and chlorine. Check for thinning, damage or loss of fit; do not rely on worn or overstretched fabric for the same protection.

For more coverage, browse Women's Rash Guards and Swim Shirts. Use sunscreen on exposed skin according to its label, along with shade and other sun protection.

Source: The Skin Cancer Foundation: Sun-Protective Clothing (reviewed by Elisabeth G. Richard, MD; updated August 2025). Fabric and care details are from the individual Berry Jane™ product listings; general guidance is not a wet-performance certification of our garments.