Between 2011 and 2016 Lewers made 74 senior appearances for England. He made his senior debut for England in June 2011 against Pakistan. He was subsequently a member the England teams that won bronze medals at the 2011 Men's EuroHockey Nations Championship and 2014 Commonwealth Games. He also represented England at the 2013 and 2015 Men's EuroHockey Nations Championships and at the 2014 Men's Hockey World Cup. In both 2014 and 2015 Lewers was named the England/Great Britain Player of the Year by the Hockey Writers' Club.