A longer hem and snug fit stop the ride-up.

Look for a rash guard with a longer hem (at least 2–3 inches below the waistband) and a compression-style fit. That’s it.

Ride-up happens because the shirt is too short, too loose, or both. When you stretch your arms overhead, the fabric pulls up from the waist. A loose shirt just slides back down wrong — but a snug shirt stays put because there’s no slack to bunch.

The material matters too. Avoid shiny, slick polyester blends. Look for a heavier-duty nylon-spandex mix with some texture. Some rash guards have a silicone gripper strip inside the hem — that helps a lot if you’re doing serious swimming or paddle sports.

Don’t buy a baggy “beach shirt.” Those are for sun protection while standing still. For actual movement, you need something that fits like a second skin.

One final thing: if you’re between sizes, size down. The stretch will keep it comfortable, and it won’t ride up on your first dive.