Girl In One-piece Swimsuit

As an alternative to a swimsuit, some people wear trousers, underpants or a T-shirt either as a make-shift swimsuit or because they prefer regular clothes over swimsuits. In some countries, such as Thailand, swimming in regular clothes is the norm while swimsuits are rare. At beaches, this may be more accepted than at swimming pools, which tend not to permit the practice because underwear is unlined, may become translucent, and may be perceived as unclean.
In New Zealand English
In New Zealand English, swimsuits are rarely called anything other than togs or, less usually, bathers. They are less commonly called "cossies". The term "togs" is less common in other parts of the Commonwealth, where it can also refer to clothes in general.