Arriving by boat

From Italy to Patras
There are many connections across the Adriatic Sea and a few ferry companies operate between the Italian ports of Brindisi and Ancona and the port of Patras.
If you have your own car take the road to Korinthos and then on to Athens (220 km). Be extremely careful as this poor excuse for a national road is very dangerous and accidents happen very often.
If you're traveling without a car take the intercity bus (KTEL) to Athens central station which costs €18.90.

From the islands to Piraeus
If you arrive in Piraeus on a boat, chances are that you'll disembark  within walking distance from the  metro terminal. If you are too far (i.e. the cruise liner's dock) or your luggage is too heavy there is a free bus service that runs inside the harbour. Try to avoid taxis but if it is neccesary to use one, then pick one up from the street outside the harbour area.