In May 2005 he was appointed assistant to Don Givens as manager of the Republic of Ireland under-21 team. In August of the same year, Eastick was appointed a national coach with the FA and took responsibility for the England under-18 side. When Martin Hunter stepped down in June 2006 to take up a role as first-team coach with Norwich City, Eastick stepped up to take charge of the under-19s. He led that team to the final of the 2009 European Championships, before taking over as head coach of the England under-20 team, from the 2009 under-20 World Cup finals until the 2011 competition.