At the 2012 Summer Olympics in London, Sjöström competed in four individual events, reaching the semi-finals of the 50 m freestyle, 100 m freestyle and 200 m freestyle, and finishing 4th in the final of the 100 m butterfly in a time of 57.17. Sjöström's world record was broken in this race by Dana Vollmer of the United States. In 2015 however Sjöström regained the world record by improving it twice at the World Championships in Kazan.