For the ones in a hurry
From Korinthos-Patras national highway you will reack the Rion-Antirrion bridge. Cross the bridge towards Nafpaktos. 20 kilometers after Nafpaktos (towards Itea-Galaxidi) you will find Marathias.
For an excursion:
Follow the Athens-Lamia national highway, and exit towards Thiva-Livadeia and continue towards Amfissa-Itea-Galaxidi. Driving to Nafpaktos about 40 minutes after Galaxidi you will find Marathias.
Have a nice trip!