Two-Tone Swimsuit vs Women's Bottom Turn Racerback Bikini Top: which is safer?
Patagonia Women's Bottom Turn Racerback Bikini Top is the clear pick. Onia Two-Tone Swimsuit carries a failing PFAS grade, and we never recommend buying a failing product.
Onia
Two-Tone Swimsuit
PFAS grade
Overall grade
Verdict
Hazard flags
Material
Confidence
PossiblePFAS in water-repellent coating (water-repellent coating) coating
ReportedMicroplastic fiber shedding
LikelyFabric degradation from chlorine, salt, and UV
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 durable water-repellent (DWR) coating, Microplastic fiber shedding and Fabric degradation from chlorine, salt, and UV on the Onia and not on the Patagonia.
- We flag Elastane (spandex) degradation under heat or chlorine on the Patagonia and not on the Onia.
- The Onia is Nylon/polyester blend with water-resistant treatment 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 Onia grade, at 42% 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