If you own or rent a car, you can easily get from Athens to Hydra in 2 hours and 45 minutes. Through Attiki Odos, get on the National Road Athens – Corinth and make a left after the canal heading towards Epidauros (Corinth Exit B - Epidavros).
Drive for about 30 minutes and you reach the intersection of Epidaurus. Before getting there, you will see signs to Poros or Spetses. At the junction turn right and immediately drive under the bridge and make a left.
Then, follow the new road, making sure you don’t miss the sign to Poros. At this point, slightly turn left for Poros and you will reach Galata in 30 minutes. You continue on the coastal road and in a half an hour you reach Metochi. Your trip from Athens to Metochi will approximately last 2 hours and 30 minutes.
From Kranidi, Porto Xeli, Kosta or Ermioni, you reach Metochi by following the coastal road with your car, in approximately 45 minutes.
Metochi is a location opposite from Hydra, where there is a free public parking to leave your car and then come across to Hydra with daily departures of the boats "FREEDOM Ι", "FREEDOM ΙΙ" & FREEDOM III , or "METOXI EXPRESS"that lasts approximately 12 minutes.
From Metochi you can also reach Hydra or vise versa, with a sea taxi.