On the 12 December, 2020, Gatt qualified at age 15 for the 2020 Tokyo Summer Olympics for the 1500m freestyle race with a time of 17:00.28. Later, on the 6 June, 2021 Sasha Gatt also qualified for the 400m freestyle race at a time of 4:18.58.
Gatt was in heat 2, lane 7 for the 400m freestyle race.[5] With the time of 4:19.75, she finished 6th in her heat and 22nd in the event. The next day, she swam in the women's 1500m freestyle race.[6] Gatt finished third out of three in her heat, with a time of 16:57.47, which was her PB.[7]
In July 2024, Gatt was one of five athletes who represented Malta during the 2024 Paris Olympics.[8] She together with Gianluca Chetcuti carried the Maltese flag during the opening ceremony.[9] She competed in the 1500m freestyle heats at the Paris Olympics and later tested positive for COVID-19. She finished a distant third with a time of 17.00.54.[10]
