Izaac Keith Stubblety-Cook ( ; born 4 January 1999) is an Australian swimmer.
He has won four Olympic medals, including gold in the 200 m breaststroke at the 2020 Olympics. He was also the 2022 world champion and a former world record holder in the event.
Stubblety-Cook started swimming at Wellers Hill Water Ratz, a swimming club in Tarragindi, Queensland. His reason for joining was to participate in the swim program for general water safety.
Stubblety-Cook competed at the 2017 World Junior Championships in Indianapolis. Individually, he won the bronze medal in the 200 m breaststroke. He initially came 4th in the 4 ÃÂ 100 m medley relay, but was promoted to the bronze medal position in 2018 after the gold medalists were disqualified for a doping violation.
Stubblety-Cook won a silver medal at the 2018 Pan Pacific Championships in the 200 m breaststroke with a personal best of 2:07.89.
At the 2019 World Championships in Gwangju, he came fourth in the 200 m breaststroke in a time of 2:07.36.
Stubblety-Cook qualified for the Tokyo Olympic team at the 2021 Australian Trials, recording 2:06.28 in the 200 m breaststroke. This broke Matthew Wilson's Australian record of 2:06.67 from 2019.
At the Tokyo Olympics, Stubblety-Cook won the gold medal in the 200 m breaststroke, setting an Olympic record of 2:06.38. He then competed in the mixed 4 ÃÂ 100 m medley relay, which was the event's inaugural appearance at the Olympics. Australia won the bronze medal. He concluded the Olympics with the men's 4 ÃÂ 100 m medley relay, where Australia finished 5th.
At the 2022 Australian Championships in Adelaide, Stubblety-Cook broke the world record in the 200 m breaststroke, recording 2:05.95. This surpassed Anton Chupkov's mark of 2:06.12 from 2019.
At the 2022 World Championships in Budapest, Stubblety-Cook came seventh in the 100 m breaststroke. Swimming the breaststroke leg of the mixed 4 ÃÂ 100 m medley relay, he won the silver medal. Stubblety-Cook later won the gold medal in the 200 m breaststroke in a time of 2:07.07.
At the 2022 Commonwealth Games, Stubblety-Cook won the gold medal in the 200 m breaststroke and mixed 4 ÃÂ 100 m medley relay events, establishing a games record in the latter. He won silver medals in the 100 m breaststroke and men's 4 ÃÂ 100 m medley relay.
Stubblety-Cook qualified for the 2023 World Championships. His first medal of the championships came in the mixed 4 ÃÂ 100 m medley relay, where Australia finished second. He then competed in the 200 m breaststroke. He won the silver medal in the event, and his world record was broken by gold medalist Qin Haiyang. In his final swim of the competition, he won the bronze medal in the 4 ÃÂ 100 m medley relay.
At the 2024 Olympics, Stubblety-Cook won silver in the 200 m breaststroke. He swam in the heats of the mixed 4 ÃÂ 100 m medley relay. He was replaced by Joshua Yong in the final, and Australia went on to win the bronze medal.
In October 2024, Stubblety-Cook moved to Melanie Marshall's program on the Gold Coast. This was prompted by the retirement of Stubblety-Cook's longtime coach, Vince Raleigh.
Stubblety-Cook qualified for the 2025 World Championships, but later withdrew due to a back injury.