They are made of Spandex and nylon or polyester, a fabric that is lightweight, quick drying, flexible, durable, and naturally antibacterial.
On their own they provide light coverage in warm summer temperatures for many water sports including surfing, scuba diving, snorkelling, wake-boarding, body surfing, body boarding, windsurfing, kayaking, and of course for swimming.
Rash vests are most often worn when the weather is too warm for a wetsuit. They also help prevent irritation caused by rapid impact with surface water and waves as happens in some splash sports. Anybody who ever got stung by a belly flop knows what we mean.
It all started in the 1980's when swim shirts were mostly worn as rash guards by surfers
to avoid sunburn or body rash from the surf board wax.
Today swim shirts are used with most water sports
like swimming, surfing, skim-boarding, scuba diving, snorkeling, wake-boarding, and more.
Swim shirts have become part of basic swimwear for men and women
because they dry fast just like board shorts and give protection from wind, UV rays and hard waves.
Surfers wear rash vests to prevent wax-based chafing from sliding on and off the surf board. The board's wax holds sand from the beach that would rub against the surfer's torsos as they paddle out to the break.
Rash vests also offer some protection against jelly fish stings and have a high Ultraviolet Protection Factor (UPF) to protect against sunburn.
Rash vests are thought to have originated in Australia, where they are commonly referred to as "rashies" or "rashys." Variations of the rash vest have made their way into many other sports including baseball, American football, water polo, Jiu Jitsu, and mixed martial arts.