Swimsuits can be skin-tight or loose-fitting. They are often lined with another layer of fabric if the outer fabric becomes transparent when wet.
Swimsuits range from designs that almost completely cover the body to designs that expose almost all of the body. The choice of swimsuit will depend on personal and community standards of modesty and on considerations such as how much or how little sun protection is desired, and prevailing fashions. Almost all swimsuits cover the genitals and pubic hair, while most except thongs cover much or all of the buttocks. Most swimsuits in western culture leave at least the head, shoulders, arms, and lower part of the leg (below the knee) exposed. Women's swimsuits generally cover at least the aereola and bottom half of the breasts, but some are designed for the top part of the swimsuit to be removed . In many countries, young girls and sometimes women choose not to wear a swimsuit top, and this can vary with the occasion, location, age, etc. Men's swimsuits which cover the upper body are relatively rare in western culture.
Both men and women may sometimes wear swimsuits covering more of the body when swimming in cold water (see also wetsuit and dry suit). In colder temperatures, the swimwear is needed to conserve body heat and protect the body core from hypothermia.