How long does water-resistant sunscreen last?

Water-resistant sunscreen lasts either 40 or 80 minutes — those are the only two durations the FDA allows. The label will say “water-resistant (40 min)” or “80 min,” and you must reapply after that time if you’re in water or sweating. Even if you barely get wet, the clock starts when you get wet or sweat. For non-water activities, reapply every two hours or after towel drying.