There are two primary ways to arrive in Delphi: by bus and by your own car. Certainly, each has its merits, but depending on your preference, one method might be better for you than the other. 

Perhaps the most popular way to get to Delphi from Athens is by bus. The trip, which takes about 3 hours and includes a brief rest stop, is the preferred method for many people who don’t want to do the drive themselves. In addition, Delphi is often a day trip for people visiting Athens, so this is an easy side journey, although it would make it a long day if you visit the museum (well worth it and recommended) as well as the archaeological site itself. 

Buses from Athens to Delphi depart from bay no. 7 (usually, but check when buying your ticket) of Terminal B bus station (aka 260 Liossion Street). You buy the ticket at the booth marked with the destination "Amfissa", which is E15.10 one way; E30.20 return.  

As at 5 June 2013, the reduced bus service timetable between Athens and Delphi and vice-versa was as follows (info provided by the KTEL employee manning the Amfissa ticket booth):

Athens to Delphi - Daily (including Sundays):  07.30, 10.30, 14.30 & 18.15;

Delphi to Athens - Daily (including Sundays):  06.00, 11.00, 15.00 & 18.45.

Buses from Delphi to Athens depart from outside the closed down hotel, near the large plane tree, opposite the kiosk at the bottom of the main street as you head towards the museum/site. 

The employee said that extra services may be put on later this summer (2013), but this is not definite. She also strongly advised that before finalising plans to travel to Delphi from Athens (and vice-versa), one should first telephone to check on the latest timetable (at the telephone number provided below), as the online timetable is not always up to date or correct .

The official website is:http://www.ktel-fokidas.gr. KTEL Fokidos is the one serving Delphi and its phone number is +30 210 831 7096.  (For more information, you can also visit www.ktel.org.)

If you already have a rental car, or would prefer to do the driving yourself, you can certainly do this (though you will park the car once you arrive in Delphi and walk). Many people don’t want to take the drive because it’s a long, windy road up the mountains to Delphi and can be treacherous, which makes the bus preferable to many people.

There is no direct train service from Athens to Delphi.