Other notable Olympians with June 30 birthdays, according to sports-reference.com: 1964 10,000m champion Billy Mills (1938), 2008 1500m champion Asbel Kiprop (1989) and 2014 ski halfpipe champion David Wise (1990).
But back to Phelps. He has more Olympic medals (22) and golds (18) than any other Olympian and could become the first U.S. man to swim in five Olympics in Rio de Janeiro. Dara Torres, whom Phelps called “mom” when he swam in 2000 at age 15, is the only other American to swim in five Olympics.
Here are 30 photos of Phelps, in chronological order, in honor of his birthday (courtesy AP, Getty Images, Baltimore Sun, Phelps’ Instagram):
Phelps, 8, at the North Baltimore Aquatic Club in 1993.
Phelps, 14, at the U.S. Championships in March 2000.
Phelps stretches before swimming the 200m butterfly at the 2000 U.S. Olympic Trials. He made the team and was the youngest U.S. swimmer in Sydney.
Phelps swims at the Sydney Olympics, where he finished fifth in the 200m fly.
Phelps returns to Towson (Md.) High School after the Sydney Olympics.
Phelps visits the White House with the U.S. Olympic Team in 2000. Bill Clinton was president.
Phelps celebrates his first world record on March 30, 2001. He swam the 200m fly in 1:54.92. His current world record in the event, from 2009, is 1:51.51.
Phelps, next to Tom Malchow, holds his first World Championships gold medal from the 200m fly in 2001.
Phelps poses with his first major American rival, Ian Crocker, who beat Phelps for 100m fly gold at the 2003 World Championships.
Phelps celebrates after winning his first Olympic gold medal in the 400m individual medley in Athens.
Phelps holds his bronze medal from the “Race of the Century” in Athens, when he nearly chased down Ian Thorpe and Pieter van den Hoogenband in the 200m freestyle.
Phelps poses with a wide-eyed Ryan Lochte after their first Olympic head-to-head race in the 2004 200m individual medley. They went one-two.
Phelps cheers on the U.S. 4x100m medley relay team in Athens after giving up his spot to Crocker for the final. Phelps still won a medal, his sixth gold and eighth overall of the Games, because he swam in the morning prelims.
Phelps visits MTV’s “Total Request Live” after returning from Athens.
Phelps at the 2007 World Championships, where he set the table for Beijing 2008 by winning seven gold medals in eight events. His quest for eight was thwarted in the final event, when Crocker left the blocks too early in the medley relay prelims.
Phelps shakes hands with Mark Spitz at the 2008 U.S. Olympic Trials. Phelps broke Spitz’s record of seven gold medals at a single Games at Beijing 2008.
Garrett Weber-Gale and Phelps celebrate the U.S. 4x100m free relay gold in Beijing. Anchor Jason Lezak swam the fastest relay split in history to overtake Frenchman Alain Bernard.
Phelps, left, and Milorad Cavic, right, finish in the 100m fly in Beijing. Phelps won by .01 of a second.
Phelps with his mom, Debbie, and sisters, Hilary and Whitney, after winning gold No. 8 at the Beijing Olympics.
Phelps hosts “Saturday Night Live” in September 2008. That’s William Shatner on the right.
Phelps meets another president, George W. Bush, after the Beijing Olympics.
Phelps slaps his suit in one of his most exuberant individual swim reactions upon winning the 100m fly at the 2009 World Championships. The 2009 Worlds were the apex of the controversial high-tech suit era. Earlier, Phelps was beaten in the 200m free by German Paul Biedermann, who wore a rival Arena suit to Phelps’ Speedo.
Phelps reacts after finishing fourth in the 400m IM at the London Olympics. It was his first event of the Games and his first time finishing out of the medals in an Olympic event since 2000. Doubts surfaced over his medal hopes for the rest of his individual events.
Phelps, who rebounded to win six medals (four gold) in London, lifts a trophy recognizing his feat as the most decorated Olympian of all time.
Phelps might have thought this was his final White House visit in September 2012.
Phelps, who retired after the London Olympics, in the background with Michael Jordan at Jordan’s celebrity golf tournament in April 2013.
Phelps takes a swing at one of his many retirement golf trips, this one in Crans, Switzerland, in September 2013.
Phelps and soccer legend Pele at a Subway event in December 2013 in Sao Paulo, Brazil. Pele was promoting the World Cup. Many wondered at the time whether Phelps had designs on returning to Brazil in 2016.
Phelps practices at the Charlotte Grand Prix in May 2014, his second comeback meet.