Long course events have been competed since the inaugural edition of the championships in 1973. The youngest male swimmer to participate in the World Swimming Championships was Ahnt Khaung Htut from Myanmar, who was 12 years old in 2015. He took part at the 100m backstroke and 100m breaststroke events. The youngest female swimmer to participate in the World Swimming Championships was 10-year-old Alzain Tareq from Bahrain in 2015. She participated at the 50m butterfly and 50m freestyle events.