Costa sunglasses aren't designed to float on their own. However, you can use a floating leash or cord to ensure they stay afloat if they happen to fall into the water during activities like fishing, boating, or exploring. Additionally, some Costa models, such as the Cat Cay, feature temple holes where you can attach a retaining strap. Costa also offers retainers specifically designed to keep your sunglasses secure and in place while you're outdoors.