is changing the laws at the moment so that you do not have to report to port police when you arrive at every port except for your first entry port. Most non_EU sailors went through the tedious process of getting a transit log and then going to the port police whenever they came to you. Most villages don'have port police. We went to 3-4 port police in 3 months sailing.
Now this is changing and it' s not clear what exactly will happen. I think when you arrive in Greece you will pay a hefty fee (400 euros for less than 12 metres, 800 and more on a sliding scale for boats more than 12m)…after that, you might not have to do anything. In June this year it was the old way There is still some confusion about how this will work
and so it might be a bit of the old scheme and a bit of the new.. SSomeone in Greece now might know where it' s up to at the moment. The rules for EU citizens might be different