National Bikini Day

National Bikini Day is observed every year on July 5 to mark the debut of the modern bikini in 1946. The design was introduced by Louis Réard, a French engineer and lingerie shop owner, who named it after the Bikini Atoll in the Pacific—the site of recent nuclear tests. Réard’s goal was to create something explosive for the fashion world, and he succeeded. His design featured just 30 square inches of fabric, exposing the navel for the first time in a swimsuit. Since no professional model was willing to wear it due to its revealing nature, he hired Micheline Bernardini, a nude dancer, to model it at a Paris pool.

The timing of the bikini’s release was influenced by post–World War II fabric rationing, which encouraged minimalist swimwear. Although two-piece swimsuits had been seen as early as the 1930s, Réard’s design marked a shift in how much skin women could show in public—and it sparked immediate controversy. The Catholic Church, many European countries, and even some U.S. states banned the bikini. Still, it gained traction in Europe, especially after actress Brigitte Bardot was photographed wearing one at the Cannes Film Festival in the 1950s.

As societal norms evolved, the bikini became a symbol of freedom, body positivity, and women’s autonomy. It gained mainstream appeal in the 1960s with pop culture milestones such as Ursula Andress emerging from the ocean in Dr. Noand the release of Sports Illustrated’s first Swimsuit Issue in 1964.

Today, National Bikini Day honors this cultural shift, the continued evolution of swimwear, and the broader movement toward self-expression and body confidence.

When is National Bikini Day?

National Bikini Day is celebrated every year on July 5, marking the anniversary of the bikini’s debut in 1946.

Here’s when it falls through 2030:

Similar and Related Days

• National Swimsuit Day (May 20): A celebration that kicks off summer swim season and encourages confidence in all types of swimwear.
• National Beach Day (August 30): A day to enjoy and preserve beaches, often linked to swimwear and water-related activities.
• National Sunscreen Day (May 27): Highlights the importance of sun protection during swimsuit season.
• World Body Confidence Day (May 13): Promotes self-love and acceptance across all body types and expressions.

In addition to National Bikini Day, there are over two-hundred other fun national days to celebrate in July alone.

When Did National Bikini Day Start?

National Bikini Day has been celebrated since at least 2011, when Business Insider published an article about it. Since then, the day has gained traction each year on social media and has been recognized by outlets like The Sun and Teen Vogue.

A Brief History of the Bikini

Though the modern bikini was introduced in the 20th century, two-piece garments for women have a history going back thousands of years:

• In ancient Greece and Rome, women athletes wore garments that closely resemble bikinis. Mosaics from the Villa Romana del Casale in Sicily (c. 300 AD) show women in bikini-like outfits lifting weights and playing sports.
• The Roman terms subligaculum and strophium referred to undergarments used by women for athletic and performance activities.
• In the 19th and early 20th centuries, modesty in swimwear was strictly enforced. Bathing suits often included full skirts and sleeves.
• Annette Kellerman, a pioneering swimmer, was arrested in 1907 for wearing a form-fitting one-piece, yet her swimsuit set the stage for future designs.
• The 1940s wartime fabric shortages led designers to experiment with smaller swimsuits, setting the stage for Réard’s 1946 creation.

Fun Facts About the Bikini

• The earliest known depiction of bikini-style clothing dates back to 5600 BC. A statue from Çatalhöyük, in modern-day Turkey, shows a woman wearing a leopard-print two-piece outfit.
• The term “bikini” was inspired by nuclear testing at the Bikini Atoll, chosen because Réard believed the impact of his design would be as explosive as the bomb.
• Micheline Bernardini, the first model to wear the modern bikini, received over 50,000 fan letters after the swimsuit’s debut.
• Despite its debut in 1946, bikinis were banned from the Miss World pageant after the first winner was crowned wearing one in 1951. That ban lasted for decades.
• Raquel Welch’s fur bikini in One Million Years B.C. (1966) became one of the most iconic images of 20th-century cinema and launched countless posters.
• The bikini gave rise to entire industries, including bikini waxing, spray tanning, and an annual billion-dollar swimwear market by the early 2000s.
• According to surveys, most bikinis never touch the water—they’re often worn for sunbathing or fashion purposes only.
• The most expensive bikini ever made was designed in 2006 by Susan Rosen and was valued at $20 million, made entirely of diamonds and platinum.
• Variations of the bikini have spawned their own names, including monokini, tankini, seekini, and even microkini.
• In some parts of the world, bikinis remain controversial. Cities like Barcelona have passed laws banning bikinis in non-beach public areas.

Before You Go:

We have many more national days lists for you to explore.

• Food-related national days: complete list of national food days, pasta & noodles days, vegan & vegetarian days, mushroom days, ice-cream days, pizza days, coffee days, chocolate days, wine days, alcohol & drinking days.
• Non-food national days: National Days Calendar 2025 (check out the printable calendars in my Etsy shop), National Days for Teachers, and a wide array of special lists such as cat days, dog days, animal days, cleaning & organizing days, book days, music days, family & relationships days, national days for women, stationery days and even Harry Potter days.
• Country-specific national days: Australian national days, more coming soon.

📝 This article was originally published on June 17th, 2021. It has been thoroughly updated, and the publishing date has been changed to reflect the new version.