Iraklia is the westernmost of the Small Cyclades, a quiet, hilly island between Naxos and Schinoussa where the harbour village of Agios Georgios is the centre of island life. People come for walking trails, empty coves and a pace that the bigger islands lost long ago. Getting home to Athens from here is a proper journey, and the direct ferry to Piraeus saves you changing boats on Naxos.
Expect a travel day rather than a hop. Our route data puts the crossing at about 5 hours in the main season and up to about 9 hours on winter sailings, because ships heading for Piraeus call at other islands on the way. The boats are conventional ferries, so you can walk around, eat on board, sit out on deck and, on the longer sailings, book a cabin.
Our data lists two operators on this route: Blue Star Ferries, whose large ships connect the Small Cyclades with Piraeus, and Small Cyclades Lines, the local company best known for the little Express Skopelitis. Check on the booking page whether the sailing you pick on a given day is a straight run to Piraeus or involves a change, as the itinerary makes a big difference to the arrival time.
Because sailings are limited to a few days a week, pick your boat before you book your last nights on Iraklia, and keep a margin before any flight from Athens. Piraeus is well connected to central Athens and the airport, but arrivals after a long crossing can run late when the wind is up.