Port is Piraeus. It is a good 25 - 30 minute walk to the Metro. You walk through the port parking lot and hang a left. You might catch a bus but you have to Greek currency. You might get a cab - but we found them not willing to take us to the metro. To be honest with you with the state of unrest in Athens right now. I would not be making my way by cab nor by metro to the Acropolis. If I were to venture to Acropolis and Plaka, I would certainly take a tour. Because of the riots, etc. happening there now, I would not want to be stuck in Athens unless I was on a ship sponsored tour and then I know the ship would wait for me. Secondly,if things progress any worse, the cruise lines may simply not offer the tours. They are not going to want expose themselves to risk. With all the unrest, there is also a much greater possibility of the Greeks staging their famous wildcat two to four hour strikes against transit, etc... Stay safe while visiting Athens or simply do not attempt the Acropolos at all. There are lots of other tours that will take you out of Athens. Ship tours that is. Check other excursions RCCL offers to outside Athens. Stay safe.