The tankini is a bathing suit combining a tank top, mostly made of spandex-and-cotton or Lycra-and-nylon, and a bikini bottom introduced in the late 1990s. This type of swimwear is considered by some to provide modesty closer to a one-piece suit with the convenience of a two-piece suit, as the entire suit need not be removed in order to use a toilet. Tankinis come in a variety of styles, colors, and shapes, some include features such as integrated push-up bras. It is particularly popular as children's beachwear, and athletic outfit good enough for a triathlon. According to Katherine Betts, Vogue's fashion-news director, this amphibious sportswear for sand or sea lets users go rafting, play volleyball, and swim without worrying about losing their top.

A tank top consists of a sleeveless shirt with low neck and adjustable shoulder straps that vary in width and style. It is named after tank suits, one-piece bathing costumes of the 1920s worn in tanks or swimming pools. The upper garment is worn either by men or women, having a greater variety of models available for women. In men it is usually used as underwear.