Long has represented England from U16 to U20 level. He made two appearances in the U16s' victorious 2010–11 Victory Shield campaign. Long was elevated an age-group and named in the England squad for the U20 World Cup in June 2013. He scored on his debut for the side in a 3–0 pre-tournament friendly victory over Uruguay. He made substitute appearances against Egypt and Iraq as England crashed out in the group stage. Long made his U19 debut in a friendly versus Hungary on 14 November 2013. Long scored his second U20 goal in a 3–2 Four Nations Tournament victory over the Netherlands on 11 October 2014.