 In January 2012, Tziolis joined Monaco for a reported transfer fee of €200,000.On 31 August 2012, Tziolis joined Cypriot side APOEL on a season-long loan deal from AS Monaco.During his loan spell at APOEL, he became a league champion for the first time in his career, appearing in all but two of the league matches and helping his team to win the Cypriot First Division.