Sea bathing is swimming in the sea or in sea water and a sea bath is a protective enclosure for sea bathing. Unlike bathing in a swimming pool, which is generally done for pleasure or exercise purposes, sea bathing was once thought to have curative or therapeutic value. It arose from the medieval practice of visiting spas for the beneficial effects of the waters. The practice of sea bathing dates back to the 17th century but became popular in the late 18th century. The development of the first swimsuits dates from the period as does the development of the bathing machine.

A swimsuit is an item of clothing designed to be worn by people engaging in a water-based activity or water sports, such as swimming, diving and surfing, or sun-orientated activities, such as sun bathing. Different types may be worn by men, women, and children. A swimsuit can be described by various names, some of which are used only in particular locations or for particular types of suit, including swimwear, bathing suit, bathing attire, swimming costume, bathing costume, swimming suit, swimmers, swimming togs, bathers, cossie, or swimming trunks, besides others.