It is quite simple to get to Methana and there are two ways to get there by land or by sea connection. By land you just drive towards Corinth on the highway or you take a bus to Galatas. By car you turn right at the Isthmus towards Epidavros, Poros and Galatas.
By sea you take a ferry boat or a flying dolphin from Pireas towards Methana or Poros.

Times
Car: 2,5-3,5 hours
Bus:  3,5-4 hours
Ferry boat: 2,5 hours
Flying Dolphin: 60 minutes + 30 minutes Taxi from Galata to Methana