A rash guard is a type of water wear, an athletic shirt made of spandex and nylon or polyester. The name rash guard reflects the fact that the shirt protects the wearer against rashes caused by abrasion. These shirts can be worn by themselves, or under a wetsuit. A rash guard by itself is used for light coverage in warm to extreme summer temperatures for several watersports including surfing, canoe polo, water survival training, jungle environment, scuba diving, snorkelling, freediving, wakeboarding, body surfing, body boarding, windsurfing, kitesurfing, kayaking, or simply for stand up paddle surfing or swimming.
Rash guards are most often worn in surfing when the weather is too warm for a wetsuit, and to prevent wax-based chafing from sliding on and off of the surf board, on either the torso, or the legs. Rash guards also offer some protection from the sun (measured by its Ultraviolet Protection Factor) and slight protection against jelly fish stings and are sometimes worn under wetsuits to prevent chafing. A rash guard helps to prevent irritation caused by rapid impact with surface water and waves as well.