Fit matters more than the UPF label

Yes, UPF 50+ is what you want, but that number assumes the fabric is snug against your skin. A loose rash guard stretches open when you move, letting UV through the gaps — which defeats the purpose.

So focus on fit first. Look for a snug (not tight) fit, long sleeves, and a high collar or mock neck. Thumbholes help keep sleeves in place during swimming or paddling. Nylon-spandex blends last longer than polyester and hold their shape better. Avoid anything with cotton — it soaks up water, gets heavy, and loses UPF when wet.

Brand doesn’t matter as much as construction. A $30 rash guard from a solid outdoor brand (like O’Neill, Columbia, or Baleaf) works just as well as a $80 one. Replace it when it starts to fade or lose elasticity.

Your rash guard is a tool — treat it like one.