Considered among the greatest Cretan talents in his generation, and having already received call-ups for the Greek national U–19 team, Moniakis sparked controversy in November 2006, when he left the club as soon as he turned 18 to sign his first professional contract with Ergotelis' local arch rival OFI.
[6][7] He signed a four-year contract with the club in January 2011, and was immediately loaned out to fellow Super League side Kerkyra for six months.
He played for the Cretans until March 2015, when OFI announced that they were withdrawing from the Super League as the administration failed to meet the club's pressing financial obligations.
[9] In July 2015, Moniakis signed a contract with Greek Football League side AEL, for an undisclosed fee.
[11] In July the same year, Moniakis made his second comeback to his former club OFI, at the time playing in the Football League, signing a two-year contract.