The evolution of swimwear underwent a dramatic transformation in the 20th century as fashion trends rapidly shifted and the restrictive conventions of the Victorian era gave way to new ideals of freedom and functionality.
Early in the century, one-piece swimsuits became standard attire for women, mirroring the style worn by men and later inspiring the streamlined designs used in the inaugural years of the Olympic Games.
These suits, characterized by their close fit and aerodynamic shape, proved particularly effective in competitive sports.

The victorious English 400 m. women’s relay swimming team at the Stockholm Olympic Games. Postcard, 1912: Belle Moore, Jennie Fletcher, Annie Speirs, Irene Steer.
In 1913, the two-piece swimsuit was introduced, though it differed considerably from the modern bikini.
Despite its novel design, the garment still provided significant coverage of the midsection, and its transparent nature when wet prevented it from gaining widespread popularity until later in the century.

Alice Maison in bathing suit, standing with one foot in ocean, muff on right hand and left hand raised, ca. 1918.
The 1920s and 1930s marked a significant turning point as societal preferences shifted from simply “taking in the water” to “taking in the sun.”
Bathhouses and spas became social hubs, and swimwear designs evolved from purely functional garments to pieces that also featured decorative elements.
Although rayon was employed during the 1920s to produce form-fitting swimsuits, its lack of durability when wet presented challenges, prompting occasional use of jersey and silk as alternative materials.

Two girls in Zebra-style swimsuit, ca. 1906.
By the 1930s, a notable change occurred in men’s swimwear as well.
Shirtless swimming became increasingly common, and by the end of the 1940s, it was standard for male swimmers, even in competitive events, to don attire that merely met public decency standards.
This trend toward minimal coverage also extended to other sports, such as professional boxing and wrestling, where a bare-chested look became the norm.

Annette Kellerman in her famous custom swimsuit, ca. 1900.
Throughout the 1930s, significant design innovations emerged: necklines dropped dramatically at the back, sleeves vanished, and side panels were removed to create a more contoured fit.
The advent of new fabrics like latex and nylon further contributed to this trend, with swimsuits gradually beginning to hug the body and featuring adjustable shoulder straps that allowed for tanning.

Swimmer Annette Kellerman, in her swimwear full length, lying on floor, facing front. Not dated. Probably late 1900s or early 1910s.
Influential designers also left their mark on swimwear during this era. Coco Chanel popularized the suntan as a fashionable attribute, while in 1932, French designer Madeleine Vionnet introduced an evening gown with an exposed midriff, a design that soon appeared in the film Gold Diggers of 1933.

Family in front of beach chairs, ca. 1900.
In 1935, American designer Claire McCardell advanced swimwear design by eliminating the side panels of a maillot-style bathing suit, paving the way for the modern bikini.
The invention of the Telescopic Watersuit in 1938, crafted from shirred elastic cotton, signaled the decline of wool as the fabric of choice, and by 1939, cotton sun-tops adorned with palm tree prints, alongside silk or rayon pyjamas typically paired with a blouse, had become popular.

Woman swimwear, ca. 1905.
Competitive swimwear also experienced notable shifts during this period. A Speedo racerback silk suit, which revealed the shoulder blades, nearly led to the disqualification of swimmer Clare Dennis at the 1932 Olympics; however, this style became accepted by 1936.
Meanwhile, men’s swimwear evolved as well, with bare-chested suits gaining acceptance in 1936 and brief-style suits becoming the norm by the 1948 Olympics.

U.S. singer and Vaudeville star Arthur Fields with his wife and child, posed in swimwear with hose washing their Stutz automobile, ca. 1919.
The pressures of World War II further influenced swimwear design. To conserve dwindling supplies of cotton, silk, nylon, wool, leather, and rubber, a mandate was issued to reduce the fabric used in women’s swimwear by 10%.
This restriction led to designs that exposed more of the midriff, a change popularized by the era’s pin-up and glamour photography, although one-piece suits continued to hold a significant share of the market.

Men and a woman with bathing machines in shallow water at a beach, ca. 1913.
In the 1950s, the popularity of patterned swimsuits soared as both competitive and recreational swimwear continued to evolve.
Innovations in fabric technology, such as the introduction of Lastex and further developments in nylon, enabled the creation of more streamlined, form-fitting designs.
Men’s swimwear also began to reveal more of the body, with Speedos emerging as a favored style, marking a decisive shift toward modern swimwear aesthetics.

Phyllis Haver was a Mack Sennett’s bathing beauty, 1917.

Photograph of middle-aged man in swimwear of the era at sea beach at Bay St. Louis, Mississippi, 1914.

People attending a beauty contest held at the Tidal Basin in Washington, D.C., 1919.

Bernard Cyril Freyberg (later Sir Bernard) on a diving board over what appears to be the sea. The steep hills in the background indicate that the location is possibly Wellington. In the background a large crowd is watching the events taking place, 1914.

William T. Burgess, who swam the English Channel on Sept. 6, 1911. He was the second person to successfully complete a swim of the English Channel after Matthew Webb.

Swimmer Claire Farry, posing standing in swimsuit with her hands and feet bound by ropes, ca. 1910s.

U.S. singer and Vaudeville star Arthur Fields standing on beach in swimsuit, holding bottle at his mouth to pose as if he was drinking, ca. 1910s.

A group photo taken in the 1900s.

American actor Gloria Swanson (1899 – 1983) stands on tiptoes on the prow of a motorboat while Teddy the dog sits with his paws on the steering wheel in a still from director Clarence G Badger’s film Teddy at the Throttle (1917).

Group of bathers being photographed at Hanlan’s Point, Toronto, Canada, 1913.

Jack London at Waikiki, 1915.

Keystone studios “Bathing Beauties”. Hollywood film women in swimwear, 1916.

Marie Prevost was a Mack Sennett’s bathing beauty, ca. 1917.

Image of Mina Wylie, Dutch swimmer, Olympic silver medalist in 1912.

Olympic swimmers, 1912.

Woman in wet swimwear. Photo by Alfred Stieglitz, Lake George, Warren County, New York, 1916.

Young woman in bathing suit with small dog in front of studio backdrop of beach, ca. 1913.

Mack Sennett’s bathing beauties posed on automobile, Washington, D.C., ca. 1919.
(Photo credit: Wikimedia Commons / Flickr via David Weissmane with permission / Enhanced and upscaled by RHP).