A rash guard is a type of athletic shirt made from stretchy, quick-drying fabric. It is commonly worn in water sports like surfing, swimming, and paddleboarding. The primary purpose of a rash guard is to protect the skin from rashes caused by abrasion against surfboards or other surfaces, as well as from harmful UV rays. Rash guards come in various styles, including short-sleeve and long-sleeve options, and are often made from materials like polyester or spandex. They can also provide thermal insulation in cooler water, making them popular among athletes and enthusiasts in the water sports community.