Methana is situated on a volcanic (the Methana Volcano) peninsula, attached to the Peloponnese. It is an island-like peninsula which is often misunderstood as an island. If you are planning to visit Poros island too, Methana is just another 30 minutes drive.
It has a lovely, peaceful port and a volcano that is only 15 minutes walk from the peripheral/main road. There are lots of restaurants and coffee shops by the port. Usually very quiet with very limited tourism but some great views of other nearby islands and beautiful deep blue sea waters.