To Lily Simpson, a 30-year-old from London who moved to Copenhagen about two years ago, the Danes have a refreshingly relaxed attitude toward nudity. People don’t generally bother hiding under a towel while changing into their swimwear. And there are no laws prohibiting public nudity in Denmark, so it’s normal to see topless women sunbathing along the harbor that runs through the city or people skinny-dipping at the beach. But to Claus Jacobsen, a 36-year-old who grew up in a suburb of Copenhagen, the Danes’ comfort with nudity is a far cry from what it used to be. He remembers that, when he went to the beach with his family as a child, pretty much all women, including his mother and aunt, would be topless, which is not close to the case today. Topless or nude sunbathing still doesn’t raise many eyebrows, and he suspects that most Danes would oppose an attempt to outlaw their right to it. They just seem to be exercising that right less often these days. Torben Larson, the chairman of the Danish Naturists association (naturist is another term for nudist) told me that he was less convinced that the rate of nude bathing is universally declining—he senses that it is increasing among older Danes—but agreed that younger generations seem much less interested in nude bathing, and in other nude activities, for that matter.

This apparent retreat from public nudity is not isolated to Denmark. Among French women, topless sunbathing has been steadily falling out of fashion for years; its popularity reached a nearly 40-year low in 2021. A 2019 poll observed a similar downward trend among women in the United Kingdom, Germany, and Italy.

It’s harder to gauge how things are trending in the United States, where the push during the early 1970s to legalize nudity on public beaches was far less successful than it was in Europe. On one hand, according to a survey by one naturist organization (which obviously has a dog in the fight), more Americans are coming around to the idea of setting aside public land for nude recreation. In that same survey, the share of people who say that they’d give nudity on a clothing-optional beach a try if they knew it was safe and legal jumped from 28 percent to 45 percent from 2015 to 2021. On the other hand, many of the nude beaches that were around in the U.S. in their heyday no longer exist, says Mark Storey, a staff writer and consulting editor at Nude & Natural magazine who’s spent the past 20 years writing about clothing-optional settings.

Those that remain seem to be drawing a very different crowd than they did in the 1970s. Back then, nude beaches attracted the “less-moneyed youth” who couldn’t afford a private nudist club but could manage the often-treacherous climb down to the isolated stretches of beach where nudity was tolerated, Storey told me. Even in the 1980s, nude beaches were fairly “well-balanced in age and gender,” says Charles Daney, who’s been visiting nude beaches for 40 years and blogging about naturism for nearly 20. Today, he’s observed that old nude beachgoers tend to outnumber the young, and men far outnumber women. “It seems like the gender ratio has gone from nearly 50–50 to more than 95 percent males in some places,” Daney told me.

The decline of nude sunbathing, particularly among young women, defies simple explanation. The naturists and historians I consulted for this story offered a variety of possible reasons, such as rising populations of people from cultures and religions that aren’t as tolerant of public nudity across both Europe and America, and increasing awareness of the risk of skin cancer. But pretty much everyone I spoke with suspects that the internet has something to do with it.

In the decades before the internet, even busy public nude beaches allowed for an element of privacy. “In the 1950s, on the Île du Levant, someone with a camera would have it seized, and the film removed and used as tree decoration,” Stephen L. Harp, a history professor at the University of Akron and the author of Au Naturel: Naturism, Nudism, and Tourism in Twentieth-Century France, told me. This meant you could spend an afternoon at a nude beach with reasonable assurance that no one except those present would see you naked or even know you were there. But the proliferation of smartphones has made photography harder to police and easier to distribute, effectively dissolving “private public space,” as Sarah Schrank, a history professor at California State University at Long Beach and the author of Free and Natural: Nudity and the American Cult of the Body, puts it. Anything that happens in a public setting can easily find its way to a global audience on the internet, a reality that may make internet-savvy Millennials and Gen Zers more cautious about stripping down.