For pure pleasure, traveling by car through the Peloponnese really delivers. Four wheels are not only the easiest way to get around, but a car also provides a chance to enjoy dramatic scenery and get to out-of-the-way spots. The very best driving routes? Some point to the mountain roads that lead to Stemnitsa and Demitsana—on this journey, you’ll encounter thick forests, stone villages clinging to steep hillsides, and brooding Frankish castles. Others tout the road from Kalamata to Mystras: this scenic route rises from the Messinia plains onto the forested flanks of the Taygettus range and the ruined city of Mystras and modern Sparta. For some, the road down the Mani Peninsula can’t be beat: setting out from Kalamata, the landscape becomes starker the farther south you travel (on a highway that is barely more than one lane in places) until you reach Cape Tenaro, the mythical entrance to the underworld.
Note that even if highways have assigned numbers, no Greek knows them by any other than their informal names, which usually refer to their destination. A well-maintained toll highway, known simply as Ethnikos Odos, or National road (officially E65), runs from Athens to the isthmus of Corinth (84 km [52 miles], 1hour), and from there continues south to Nafplion and Kalamata (you can veer off to Sparta, Monemvasia, the Mani, and other places in the southern Peloponnese). A branch, Route 8a, heads east from Corinth toward Patras and Olympia and connects with the Rion bridge across the Gulf of Corinth. Have change ready, as a toll of about €1 to €3 is collected intermittently on parts of the system. From Corinth the trip to Patras takes about 1½ hours, and to Kalamata and Sparta around 2 hours.
Narrow roads cross mountainous terrain throughout the region, providing many a scenic route when not closed due to snow in winter. You'll need a GPS device and/or a good map to navigate the back roads, as well as a transliteration of the Greek alphabet—many signs on remote roads are in Greek only. Gas stations are few and far between in some places, so top off the tank when you have the chance.
If you’re renting a car in Athens, do so at the airport and drive south from there; the E94 ring road around Athens allows you to avoid the harrowing city traffic and connects with E65 south to the Peloponnese. On the other hand, bus travel into the region is so easy that you may want to travel by bus to your destination in the Peloponnese and rent a car for local exploring. You may rent a car in Patras if you are arriving on a boat from Italy or one of the Ionian islands.