A one-piece swimsuit is a usually skin-tight

Skin-tight garment

A skin-tight garment is a garment that is held to the skin by elastic tension. Many skin-tight garments are also one-piece garments.In athletics and performance applications, skin-tight garments—or 'skinsuits' provide protection from injury from dancing, gymnastics, swimming, cycling, skating,...

 one-piece swimsuit

Swimsuit

A swimsuit, bathing suit, or swimming costume is an item of clothing designed to be worn by men, women or children while they are engaging in a water-based activity or water sports, such as swimming, water polo, diving, surfing, water skiing, or during activities in the sun, such as sun bathing.A...

 worn by women and girls when swimming in the sea or in a swimming pool, or for any activity in the sun, such as sun bathing. The one-piece swimsuit usually covers a female's torso

Torso

Trunk or torso is an anatomical term for the central part of the many animal bodies from which extend the neck and limbs. The trunk includes the thorax and abdomen.-Major organs:...

. Some women wear a one-piece swimsuit because they consider it to be more modest

Modesty

Standards of modesty are aspects of the culture of a country or people, at a given point in time, and is a measure against which an individual in society may be judged....

 than a two-piece bikini

Bikini

The bikini is typically a women's two-piece swimsuit. One part of the attire covers the breasts and the other part covers the crotch and part of or the entire buttocks, leaving an uncovered area between the two. Merriam–Webster describes the bikini as "a woman's scanty two-piece bathing suit" or "a...

.

Before the popularity of the two-piece swimsuit, and then the bikini, virtually all female swimsuits were one piece, and men also wore similar swimsuits that covered their whole torso.

The most common type of one-piece suit is the maillot

Maillot

The maillot is the fashion designer's name for a woman's one-piece swimsuit, also called a tank suit. A maillot swimsuit generally consists of a tank-style torso top with high-cut legs...

 or tank suit, which resembles a sleeveless leotard

Leotard

A leotard is a skin-tight one-piece garment that covers the torso but leaves the legs free. It was made famous by the French acrobatic performer Jules Léotard ....

 or bodysuit

Bodysuit

In clothing, a bodysuit, body-liner, or body is a unisex form-fitting garment that covers the torso. The bodysuit often has sleeves and varying collars. A bodysuit is distinguished from the similar leotard by the use of snaps or hooks at the crotch. A bodysuit may be worn as a top for the smooth...

. Variants of this include halterneck

Halterneck

Halterneck is a style of strap which holds up women's clothing which features a single strap or material which runs from the front of the garment around the back of the wearer's neck, and which enables most of the wearer's back to be uncovered...

 and plunge front swimsuits, as well as wrap-round ("surplice

Surplice

A surplice is a liturgical vestment of the Western Christian Church...

") and bandeau

Bandeau

- General Attire :A bandeau , is a strapless garment worn around a woman's breasts. It may be fastened in the front or back or be sufficiently elastic so as to have no fastener at all. In a strict sense a bandeau has but two edges, although it is sometimes manufactured with a detachable halter...

 styles. The pretzel suit is another special case of the one-piece swimsuit.

Recently, athletic swimsuits have used a variety of new shoulder strap styles, including the racerback

Racerback

A racerback is a type of women's swimsuit design common today among competitive swimwear and incorporated into some types of women's clothing. The top-back of the swimsuit is not covered to provide flexibility and movement of the arms during swimming....

, fastback, and flyback styles, some of which have also been used on other athletic wear.

Another recent innovation in one-piece swimsuits is the bodyskin

Bodyskin

A bodyskin is a style of competitive swimwear worn by both female and male athletes. Bodyskins are normally made of technologically advanced lycra-based fabrics designed to hug the body tightly and provide increased speed and decreased drag resistance in the water.The bodyskin resembles the design...

, which superficially resembles a unitard

Unitard

A unitard is a skin-tight one-piece garment with long legs and sometimes long sleeves. It differs from a leotard in that a leotard does not have long legs. The garment can be considered to be a combination of a leotard and tights...

 or wetsuit

Wetsuit

A wetsuit is a garment, usually made of foamed neoprene, which is worn by surfers, divers, windsurfers, canoeists, and others engaged in water sports, providing thermal insulation, abrasion resistance and buoyancy. The insulation properties depend on bubbles of gas enclosed within the material,...

. Although these cover the entire torso, arms and legs, their function is not modesty, but reducing friction through the water for professional swimmers. Their surfaces are made of textured technical fabrics which are engineered to cut through the water in the same way as fish or shark skin.