Ferries are generally the most authentic and inexpensive way to visit Greece: they are comfortable and fast if flying makes you uneasy, and fun if you enjoy opportunities to world-watch.
Many visitors who prefer having use of their own car on holiday each year drive down to Italy and then (from Ancona, Bari, Brindisi, Trieste or Venice—we recommend Ancona and Venice) board overnight ferries across to Patras. With well-organised, speedy, modern ships that have air-conditioned cabins, good restaurants, cinemas, TV lounges and discos (not to mention great panoramas), journeys are stable and pleasant.
1st-class “Lux” cabins have an en suite bathroom, fridge and TV, and on some routes they cost almost as much as flying business class, but—if you consider that you are essentially on a luxurious floating hotel—it’s well worth the expense for overnight trips. 2nd-class offers smaller cabins (most internal, without windows), but these too all have private bathrooms. Tourist-class sleeper seats are situated in a dedicated lounge. Beverages and snacks are available 24-hours, and restaurants serve breakfast, lunch and dinner (mediocre fare at somewhat expensive prices, so you may want to bring along your own drinks and food).
There are a handful of good ferrylines, each with its own schedule, and you can book tickets through travel agents, but it’s best to buy them directly from these shipping company outlets, as they usually offer better prices and have surplus tickets when independent agencies have exhausted their allotment. Remember that summer schedules are the fullest, so your best bet is to reserve tickets well ahead of time.