In addition, he helped Sri Lanka secure three gold medals and two silver medals in all five relays, bringing his medal tally to seven gold and three silver, tying his brother Matthew for most medals won. In Windsor, Abeysinghe broke two national records in the 200-meter Individual Medley (IM) and the 200-meter Freestyle. The 200m IM record was previously held by the 2012 London Olympian Heshan Unamboowe and the 200m Freestyle record was held by his elder brother, Olympian, Matthew Abeysinghe. The next year, at the 2017 Commonwealth Youth Games in Nassau, Bahamas, Abeysinghe achieved unprecedented levels of success for Sri Lanka, winning two silver medals in the 50m and 100m Freestyle events. He became one of very few Sri Lankan athletes, and the only swimmer, to ever medal at a Commonwealth Games event. Just a few months later, Abeysinghe competed at the 2017 FINA World Junior Swimming Championships. In early 2018, Abeysinghe competed at the 2018 Commonwealth Games in Gold Coast, Australia. There, he was part of the 4x100 Freestyle Relay, the first Sri Lankan swimming relay team to ever make the final at the Commonwealth Games. Later on that year, during the 2018 Asian Games in Jakarta, Indonesia, Abeysinghe swam the second-fastest 100m Freestyle by a Sri Lankan, behind only his elder brother, Matthew. After that, Abeysinghe was set to compete at the 2018 Summer Youth Olympics in Argentina, preparing for another run at medal contention. Due to medical reasons, he was unable to compete and in his stead, teammate Akalanka Pieris attended. In December 2018, Abeysinghe competed at the 2018 FINA World Swimming Championships (25 m) in Hangzhou, China.