Greece has a history of production and consumption for recreational reasons as well as medical ones.
The Greek physician Pedanius Dioscoride described cannabis properties in his book de materia medica beneficial effects of cannabis are described. (apparently the juice is very good for earache- will try that next time!!).
Recently the Greek government has legalised medical marijuana for a number of symptoms as of writing recreational marijuana hasn’t been given the same privilege. It does seem that you could still go to prison for 5 months for possession of more than .5 grams (which is not very much!!) . However, evidently Greece is going through some very big changes with regards to their view of marijuana and it will be interesting to see where that is going.
Marijuana is not too difficult to find in Greece, there are often dealers to be found in the city squares and street corners, as well as in some of the parks. But due to the harsh laws (relative to other European countries), both dealers and punters tend to be very wary. It is rather easier to find it in the beach resorts during the summer. But by far the best way is to know someone local.