Athens, the capital and transportation hub of Greece, actually has three large commercial ports that serve passengers to the Greek islands and few ports on the mainland. The ports are actually where Greek ferries to almost all the islands depart from.
Port of Piraeus
Piraeus is the largest and busiest port of Athens. Located 10 km from the city center, the port of Piraeus can be accessed by metro (green line), bus, and taxi. This is the main departure point for ferries to all the Aegean islands, Crete, and ports of Peloponnese. Carrying about 20 million passengers per year, Piraeus is the third-largest commercial port in the world.
Port of Rafina
The second busiest port of Athens is Rafina. Located on the northeastern side of Attica, Rafina is a small port town that serves ferries to the most popular islands of the Cyclades (Andros-Tinos-Mykonos all year round, and also Paros-Naxos-Santorini in summer) and to the port of Marmari in Evia island.
As Rafina is the closest port to the International Airport of Athens (only 10 km), it is mostly chosen by visitors who want to travel directly to the Greek islands, without spending time in Athens. Rafina is connected to the airport of Athens with regular buses (every 30-60 min).
Port of Lavrion
Lavrion is a small port town on the southernmost point of Attica, very close to Cape Sounion. Till few years ago, the port of Lavrion was used mostly by cargo vessels, but recently development works were made and it also serves commercial ferries. All year-round, the port of Lavrion serves ferries to the islands of Kea and Lemnos. In summer, ferry trips are scheduled to Kythnos, Serifos and other Cycladic islands.
Around the peninsula of Attica, there are also small ports that serve only local ferries.
Ferries to Evia island: On the northeastern side of Attica, there are two ports: the port of Oropos that serves ferries to Eretria (ferries run every 20-30 min) and the port of Agia Marina that serves ferries to Nea Styra (5-6 schedules per day). Ferries to Marmari Evia also run from the port of Rafina (every 6-7 times per day).
To Salamina island: The small, non-touristic island of Salamina is located right opposite Piraeus, on the south-western side of Attica. It is linked to Athens through the port of Perama. There are ferries every 15 min from the port of Perama (Athens) to Paloukia Salamina with return. Another ferry also connects Salamina to Megara. There are ferries every 30 min from the port of Megara in western Attica to Faneromeni Salamina.