Mount Athos

Here is information on the paperwork needed, Athos,and the rest of the website gives details of the monasteries, trekking itineraries, how to get there. Couldn't see Meteora mentioned, but would think you will need to visit Thessaloniki (sp?) first to get a pass.

This site also has some information, including how to obtain permission papers and how to get to Mt Athos from Thessaloniki using bus and ferry.

Among other instructions, it says that "you must organise your visit through the Mt Athos Pilgrim's office in Thessaloniki ... at least six months before your intended visit" although it does say you may not need to book so far in advance "if you are an Orthodox pilgrim" and can be flexible with your visiting dates.

Cheers

Just to add, you have to state a reason for your visit, if you are non-Greek Orthodox, and it can not be for touristic purposes only.