Women's Strapless Belted One-Piece Swimsuit vs Women's Bottom Turn Racerback Bikini Top: which is safer?
Patagonia Women's Bottom Turn Racerback Bikini Top is the clear pick. Old Navy Women's Strapless Belted One-Piece Swimsuit carries a failing PFAS grade, and we never recommend buying a failing product.
Old Navy
Women's Strapless Belted One-Piece Swimsuit
PFAS grade
Overall grade
Verdict
Hazard flags
Material
Confidence
LikelyPFAS in water-repellent coating
PossibleAzo dyes
PossibleFormaldehyde in finishing resins
Our pick
Patagonia
Women's Bottom Turn Racerback Bikini Top
PFAS grade
Overall grade
Verdict
Hazard flags
Material
Confidence
PossibleElastane (spandex) degradation under heat or chlorine
Where these two actually differ
- We flag PFAS in DWR coating, Azo dyes, Formaldehyde in finishing resins and Microplastics shedding on the Old Navy and not on the Patagonia.
- We flag Elastane (spandex) degradation under heat or chlorine on the Patagonia and not on the Old Navy.
- The Old Navy is polyester/nylon blend with DWR finish where the Patagonia is Nylon/polyester blend with elastane (standard swimwear), which is most of the difference in these two grades.
- The gap is 70 points, wide enough that this is not a close call, and the Patagonia is the one to buy.
- We are less certain about the Old Navy grade, at 45% confidence against 72%, because it discloses less.
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