These are all churches that currently hold Orthodox services. If I can't find evidence of a church that holds regular services (house churches count), then the country does not have an Orthodox Church listed. I have included Oriental Orthodox Churches. If you know of a country with an Orthodox Church that I have missed or overlooked, please let me know.
There is not an Orthodox Church on the islands, but here it says that the Orthodox are going to build a chapel for further services.
Please pray for the Orthodox in Vanuatu!
Church of the Sign of the Mother of God, Valencia
Russian Orthodox Parish of Our Lady of Kazan, Vung Tau