Sun sleeves are better than swim shirts for this.

They give you full arm coverage without the bulk of a whole shirt, and you can pair them with any bikini or sport top you already own.

Swim shirts (long-sleeve rash guards) work too, but they’re basically a second layer you have to put on and take off. Sun sleeves are just arm tubes—slip them on over your hands, pull up, and you’re done. They dry fast, pack small, and let your core stay cool.

Look for ones with UPF 50+ and a snug but not tight fit. Brands like Coolibar, Columbia, or Baleaf make solid ones that don’t slide down. Avoid cheap Amazon no-names that stretch out after one saltwater rinse.

If you’re doing paddleboarding or kayaking where your shoulders get torched, a full rash guard might make more sense. But for swimming, snorkeling, or just being at the beach with arm protection? Sun sleeves win.