 At the 2009 National Championships, Tarwater qualified to represent the United States team in the World Championships for the third time in his career by placing sixth in the 200-meter freestyle. He also placed fourth in the 100-meter butterfly, and fifth in the 200-meter butterfly. In the preliminary round of the 4 × 200-meter freestyle, he helped the United States turn in the top qualifying time. The United States later won the event, earning Tarwater a gold medal. After the 2009 season, Tarwater decided to retire from competitive swimming and concentrate on his academic work at Oxford.
