It’s just a sign of good sportsmanship. Most players opt to trade jerseys with their opponents after an international contest—whether it’s part of a tournament like the World Cup or just a friendly exhibition game. According to an excellent 2003 article by the Washington Post’s Steven Goff, the practice dates back to the 1954 World Cup in Switzerland. The most famous swap took place in 1970 between the top players for England and Brazil—Bobby Moore and Pelé.
When a match ends, each player seeks out an opponent for the swap. In general, they trade jerseys with the guy standing closest to them, but in some cases they’ll go over to an old friend or try to position themselves near a notable rival. Quite a few players on the Italian team will have their sights on the jersey of France’s top player, Zinedine Zidane. (Goff writes about an equipment manager for the New York Cosmos who used to bring more than two dozen Pelé jerseys to each match so that all his opponents could get one.)
Players on the U.S. team get new jerseys before every international game. They can trade them on the field or give them to friends and relatives. A veteran player might collect hundreds of jerseys over the course of his career. Some shirts get tossed in the closet; others get mounted and framed.
the post-match (and sometimes halftime) tradition of players exchanging sweat-soaked shirts with members of the opposing team. According to FIFA, the first recorded instance of this ritual was in 1931 when the French team requested their English opponents’ shirts to “commemorate their historic 5-2 victory at Colombes.” Yet, the most famous swap — and the one that sparked the modern craze — was when legends of the game Pele and Bobby Moore did it after the 1970 World Cup match between Brazil and England.
But why do they do this?!
No, it’s not a perverse means of guilting an opponent into disposing of your dirty laundry, it’s actually a display of sportsmanship. After battling on the pitch for 90 minutes, the shirt exchange is a way of showing respect and camaraderie between combatants. Of course, some footballers decline to trade shirts because, well, they just don’t want some other guy’s perspiration-drench shirt. Others, meanwhile, go the opposite way and even wear the stank-moistened garment they’ve been handed as the ultimate sign of high regard. Or the desperate desire to wear any shirt, no matter how soiled.
Teams issue fresh kits for every match, so giving away shirts isn’t a big deal for players. When Pele played for the New York Cosmos, he would be provided with as many as 25 or 30 shirts to accommodate all the requests he would get — an extreme example of how the shirt of the opposing team’s best player is usually the one most desired. But aside from a legend like Pele or a superstar like Cristiano Ronaldo, shirt exchanges are usually a random affair done with the nearest opponent or one who provided a particularly praise-worthy performance.