Domínguez represented Spain at various youth levels and in 2009 was called up to the Spanish under-20 team for the FIFA U-20 World Cup. He was then named in Luis Milla's under-21 squad for the 2011 UEFA European Championship. He started in all of Spain's matches, partnering Sporting de Gijón's Alberto Botía in central defense, as the national team won the tournament in Denmark. The following year, Domínguez was included in the Spain squad for the 2012 Olympics alongside Atlético Madrid teammates Adrián López and Koke. Spain were eliminated early on however, after defeats to Japan and Honduras saw them knocked out of the tournament.