This beautiful swim suit became permanently stained the moment I applied my sunscreen. In all my years of wearing bikinis and applying sunscreen, I had never encountered this problem before. I tried my best to remove the stain from the fabric but without any luck. I even tried applying sunscreen first, waiting awhile, and then slipping the swim suit on to try to avoid further stains, but it seems that any amount of sunscreen on your skin (even mostly soaked in sunscreen) will stain this delicate fabric.
My unpopular opinion: Swim suits and sunscreen go hand in hand. The fabrics they're made with should be able to handle sunscreen ingredients without staining.
In the picture below: It's difficult to capture just how dark these stains are through a camera.