He made his debut in European competitions on 12 December 2013, playing 64 minutes in APOEL's 2–0 defeat at Eintracht Frankfurt for the last matchday of the UEFA Europa League group stage.

[3] On 26 April 2014, he scored his first official goal for APOEL, in his team's 1–2 home defeat against Ermis Aradippou for the Cypriot First Division.

[12] After he crowned 2015–16 Cypriot First Division champion for a fourth time in the row, he decided to leave APOEL as his contract with the club ended.

[13] He made his official debut with AEK on 29 June 2017, playing the full 90 minutes in a 2017–18 UEFA Europa League match against Lincoln.

"[19] Antoniadis made his comeback wearing a rugby style headguard in a UEFA Nations League 1–0 win against Greece on 24 September 2022.

[22][23] He made his debut for the national team on 14 November 2012, in a friendly match against Finland at GSP Stadium, coming on as an 87th-minute substitute in Cyprus' 0–3 defeat.