We are going to take a hired van to our Airbnb in Athens from the airport and then rent a car in Athens after staying for 2 nights to drive to the Peloponnese. Any advice on the best companies? The one we wanted told us they were redoing their fleet and prices (Athens Car Rental) and were not taking reservations right now. American Rental companies seem more expensive. I don't mind more expensive as long as they are reliable cars and reputable companies.
Rick Steves recommended Pop’s Car Rental, and they were great for our Peloponnese trip. Right car, right price. They have several locations in Greece.
It is easiest to pick up the car at the Athens and then you don’t drive in Athens.
The vast majority of car rental companies in Athens are on Leof Andrea Siggrou Avenue
Go to this Google Maps link and type Car Rental in the search box.