Lewis made her senior debut for Wales in 2010 during a qualifying tournament for the 2011 World Netball Championships. She was the 190th Wales international and, at the age of 16, she was also the youngest. She was subsequently a member of the Wales team that won the 2010 Netball Singapore Nations Cup. She was also a member of the Wales teams that won the 2013 and 2014 European Netball Championships. Lewis also represented Wales at the 2011 and 2015 Netball World Cups and at the 2014 and 2018 Commonwealth Games.