How to get to Nafplio
Travel from Athens Airport (or Athens) to Nafplio
By car From Airport (Athens) If you rent a car at the airport, it's easy to find the way to Nafplio. From the airport you drive directly onto the motorway and follow the signs first to Elefsina, then Corinth, and exit the highway on the exit of Ancient Nemea and Nafplio. After that just follow the signs to Nafplio and you are there. The road is generally very good, except for a short distance between Corinth and Nafplio which is fairly narrow and winding. Calculate two hours if you keep the speed limit. And you do, don’t you? From Athens The same applies if you start from Athens. Enter the National Road then take the Attiki Odos Highway exit towards Elefsina, then Corinth, and finally exit the highway at the exit of Ancient Nemea and Nafplio. After that just follow the signs to Nafplio.
By bus You can take a bus from Terminal A to Stathmos Kiffisos in Athens and from there another bus to Nafplio. Bus number X93 runs from just outside El. Venizelos airport's arrival hall to Stathmos Kiffisos. Buy tickets at the airport before entering. The trip lasts somewhere between a half and one hour, depending on traffic. Price approx 5 Euros. If you’re already in Athens, bus No. 051 from the intersection Zinonos and Menandrou Streets, south of Omonia, will bring you to Stathmos Kiffisos. Taxi from the centre normally costs between 5 and 10 Euros, depending on where the taxi picks you up. Stathmos Kiffisos is a major bus terminal. Find the sign that says Nafplio / Argolida, and buy your tickets there. The buses go hourly on the half hour from morning to evening (some exceptions). The journey takes two to two hours and 20 min., going via Corinth / Isthmos and Argos. Nafplio is the terminus. Price approx. 13 Euros. Discount if buying return ticket tour.
Going back to Athens Please note that the bus from Nafplio to Athens stops at Eleonas metro station (blue line) before it continues to Stathmos Kiffisos. From Eleonas the metro will take you to the centre, then continue to the airport. This will usually be a faster solution than to travel by bus till the airport. Just make sure you get on the right train, not all of them run all the way to the airport. The metro takes about 45 minutes to the airport, and departs twice every hour. You must buy a ticket in the machine at the station (8 euros in 2016). The metro runs significantly more often to the center, and costs under 2 euros.
By taxi The simplest is to get the hotel you will stay in Nafplio to pre-book a taxi for you, or contact greek-taxi.gr. A taxi trip costs approximately 150 euros, and lasts a bit over one and a half hour.
By train The train doesn’t go directly to Nafplio. But it is possible to take the "Proastiakos" train from the airport to Corinth and hire a taxi from there to Nafplio. This way, it will be cheaper to take a train to Corinth and taxi from there, than to use a taxi all the way from the airport. Ask the hotel you are staying in in Nafplio to book a taxi for you.
By Ferry Piraeus - Ermioni (Porto Heli) There is a ferry (3.5 hours) and express ferry (2 hours) from Piraeus to both Ermioni and Porto Heli, via the Saronic islands. From Ermioni and Porto Heli you can catch the bus to Nafplio. Timetables here. Another option is hiring a taxi from either Ermioni or Porto Heli to Nafplio.
Transport in Argolis
From Nafplio there are buses to various places in Argolis, check the KTEL page for details. But it is more or less necessary to rent a car / moped for a day or two if you want to visit some of the more remote sights / beaches.