Women's Contrast-Trim Swimsuit vs Women's Bottom Turn Racerback Bikini Top: which is safer?

Patagonia Women's Bottom Turn Racerback Bikini Top is the clear pick. COS Women's Contrast-Trim Swimsuit carries a failing PFAS grade, and we never recommend buying a failing product.

COS Women's Contrast-Trim Swimsuit

COS

Women's Contrast-Trim Swimsuit

PFAS grade

Good 65/100

Overall grade

Good 59/100

Verdict

Skip

Hazard flags

⚑ 1

Material

nylon/elastane blend swimsuit fabric

Confidence

72%

PossibleMicroplastic shedding during use and laundering

Our pick

Patagonia Women's Bottom Turn Racerback Bikini Top

Patagonia

Women's Bottom Turn Racerback Bikini Top

PFAS grade

Excellent 90/100

Overall grade

Excellent 86/100

Verdict

Buy

Hazard flags

⚑ 1

Material

Nylon/polyester blend with elastane (standard swimwear)

Confidence

72%

PossibleElastane (spandex) degradation under heat or chlorine

Where these two actually differ

  • We flag Microplastic shedding during use and laundering on the COS and not on the Patagonia.
  • We flag Elastane (spandex) degradation under heat or chlorine on the Patagonia and not on the COS.
  • The COS is nylon/elastane blend swimsuit fabric where the Patagonia is Nylon/polyester blend with elastane (standard swimwear), which is most of the difference in these two grades.
  • The gap is 25 points, wide enough that this is not a close call, and the Patagonia is the one to buy.

Both products run through the same public rubric: materials, coatings, brand disclosure, lab findings, and recalls, plus a beyond-PFAS hazard analysis. Grades are model-based estimates, not lab tests. How grades work →

More swimwear: see the full ranking