Since the Paris Olympics kicked off, a pair of tiny orange Dutch clogs, the unofficial pin of the Netherlands team, has become a coveted currency among the athletes. Nearly an inch long and dangling from a butterfly clutch, the pin exchanged hands between Yara ten Holte, a Dutch handball player, and Ilona Maher, the U.S. women’s rugby star, who gleefully flaunted her prize on TikTok.

“One thing about the Olympic Village is, trading pins is serious business,” Ms. Maher said last week in a post that was viewed more than 2.7 million times. “We don’t mess around trading pins, OK?”

Trading in pins — those tiny, shiny emblems made by sports delegations, federations, countries and the media outlets covering them — is a longstanding tradition at the Olympics. But the activity was subdued during the pandemic, as restrictions at the Summer Games in Tokyo and the Winter Games in Beijing prevented athletes, fans and pin collectors from getting anywhere near one another.

In Paris, however, pin mania has come roaring back, this time elevated by celebrity star power and athletes chronicling their most prized conquests on social media. With more than 14,000 international athletes gathered in the Olympic Village outside Paris, pin swapping has become the Games’ hottest unofficial sport.

“I’m a first-class pin collector,” Serena Williams declared in a video on the Paris Olympics Instagram account. A pins aficionado, she said her most prized possession was a rare find from the North Korean sports delegation, which she acquired during the 2016 Rio Games. “I would never, ever trade that,” she said.