You probably want a swim shirt.

Yes, there is a difference, but for most people at the beach or pool, a swim shirt is fine.

A rash guard is tighter, made from thicker spandex or nylon, and built to handle abrasion from a surfboard or wetsuit. It dries fast and blocks sun, but it’s also more expensive and can feel restrictive.

A swim shirt is looser, often polyester, and closer to a normal t-shirt that happens to dry quickly. It still offers UV protection and comfort, just without the snug fit and high price tag.

If you’re surfing, paddleboarding, or doing water sports where you’ll be rubbing against a board, get a rash guard. If you’re just hanging at the pool, building sandcastles, or kayaking casually, a swim shirt does the job for half the cost.

Don’t overthink it unless you’re catching waves.