Athens to Delphi by car and back
 

We will be in Athens the end of August and plan to rent a car and drive to Delphi on a Sunday for an overnight stay, returning the next day. We will be staying in central Athens. The rental car options are offices on Syngrou Street or at the airport. We want to know which office would make for the shortest, least congested trip. The route from the airport looks easier but it will take time to get to the airport.

TIA

It may take a bit more time to get to the airport but you won't have to deal with all the confusing traffic and one-way streets in an unfamiliar city. It's a vacation. Make it easy on yourselves.

I think the town office at Syngrou Avenue is much more convenient if you will stay in the centre of Athens.
Syngrou is a wide 4 lane avenue and easy to connect to the motorway that goes to the North. :)
You won't have to deal with narrow one way streets....and traffic on a Sunday morning will be minimal.