At the 2018 Commonwealth Games, Wilby won a surprise gold in the 200 metre breaststroke event with a winning time of 2:08.05, which is the fourth fastest time in the world this year (correct as of 3 August 2018). He also won a silver behind compatriot Adam Peaty in the 100 meter breaststroke with a personal best time of 59.43 seconds, and a bronze in the 50 metre breaststroke.