Mollie O'Callaghan was born in South Brisbane on 2 April 2004 and was 17 years old when she represented Australia at her first Olympics in Tokyo. She was the youngest swimmer in the squad. Three years later, she was the best in the world.
At the 2023 World Championships in Fukuoka she won both the 100m and 200m freestyle — the first woman to take that double at a single World Championships — while also breaking Federica Pellegrini's 200m world record (1:52.85) that had stood for 14 years. In Paris she won individual 200m gold in Olympic record time, beating reigning champion Ariarne Titmus head-to-head. She finished Paris with five medals and was Australia's equal most decorated athlete at the Games.
She has since defended her 200m world title at the 2025 Singapore World Championships and equalled Ian Thorpe's record of 11 World Championship gold medals — the most by any Australian swimmer. In 2025 she also set the short course world record in the 200m freestyle — 1:49.36 at the World Cup in Canada — making her the fastest woman in history over that distance in a short course pool.
World record holder. Olympic gold medallist. Double World Champion. At 21, Mollie O'Callaghan is the fastest woman in history over 200m freestyle in a short course pool. Her Lane Four program distils what drives that speed into something you can actually train with.