The IP TV Player application will help you watch online TV channels from all over the world as well as Greece. This is a FREE app built with the user in mind.
For those who are interested in trying out the application, you can download it from here.
After installing from the settings applications you should add M3U lists containing the channels you are interested in. Open Settings and select Manage Channel List.
To find the necessary lists, check here and try downloading the playlists by country, or try opening the Playlists by list language.
Alternative list of Greek channels
Have fun!