Piraeus is the main port of Athens. This is where you go to get your ferry boat or the hydrofoils and the super fast catamarans to the Greek islands. The easiest way to go from Athens to Piraeus, is by metro which takes you right to the front of Piraeus harbor.
All ferry boats to the Greek islands leave from Akti Tzelepi, Akti Kondili and Akti Poseidonos. At the first two locations the ferries, hydrofoils and catamarans leave to all major Greek islands whereas at Akti Poseidonos you can get the small ferries to the Saronic islands.
port of Piraeus provides with free bus transfer
If you travel to the Greek islands like Mykonos, Santorini, Crete, Rhodes, Patmos, Lesvos, Samos, Tinos, Santorini, Hydra, Paros, Naxos and
Crete, you have opportunities to get there by ferry boats or using a faster, but more expensive way like flying dolphins.
It is always a good idea to contact the ticket agencies(booking agents), hydrofoil or catamaran operating company to check availability, departure times, travel costs etc.
For more information according to the estimated travel time and costs check the ferries database here