There are different types, styles, designs and variants of one-piece bathing suits such as monokinis, string bodies, sling bikinis, and halter-necks. Most of them are modifications of the two-piece Bikini bathing suit that came out in the 1940s. New styles of one-piece bathing suits are still growing in popularity.

Possibly the most common form of one-piece bathing suit is the tank suit. The term tank evolved from swimming tank the old name for swimming pool. The tank suit has given way to the development of the ever popular tank top, and the tankini a bathing suit consisting of a tank top and the bottom piece of the bikini.

Another popular one-piece bathing suit is the sling bikini. It has side straps that extend upwards to cover womens chests, which then stretch over their shoulders and reach down the back to form a thong. The entire sides of the torso are revealed this way. So the sling bikini becomes a very convenient bathing suit by combining two elements (the top and the bottom pieces) into one.

The monokini was designed by an Austrian named Rudi Gernreich in 1967. It is a one-piece, topless bathing suit for women consisting of only the lower piece of the bikini. Gernreich took the term from mono-indicating single or one, and is another variant of the original two-piece bikini bathing suit. The term may also be used to refer to other one-piece swimsuits such as a sling bikini.

Other forms of one-piece bathing suits for women include string bodys, halter-necks, maillots, tank suits, plunge fronts and pretzel suits.