Early career (2010-2012) Willis competed at the
2010 Commonwealth Games, where he finished 4th in the 200-metre breaststroke, and in the
2011 World Championships, where he made the final for the same event and finished 8th. At the
2012 Summer Olympics in London, he competed in the
men's 200-metre breaststroke, finishing in 3rd place overall in the heats and qualifying for the final where he finished in 8th place. He was one of the very few British swimmers to achieve a personal best at the 2012 Olympics.
Later career (2012-present) Willis finished 4th in the
2013 World Championships and in the
2013 European Championships (SC) (both in the 200-metre breaststroke). He finished 4th in the
2014 European Championships and went on to win a bronze medal at the
2014 Commonwealth Games in the 200-metre breaststroke final in Glasgow. He finished 4th in the
2015 World Championships and won a bronze medal in the
2015 European Championships (SC) in the 200-metre breaststroke. He participated in the
2016 European Championships, and finished 4th in the final of the 200-metre breaststroke in the
2016 Summer Olympics in Rio. He went on to win a silver medal in the
2016 World Championships (SC). Willis made the final for both the 100-metre and 200-metre breaststroke in the
2018 Commonwealth Games, where he finished 8th and 4th respectively. In July 2018, Willis retired from competitive swimming. == Personal bests ==