The journey takes about 50 minutes and costs around €50 during the day (from 5 am to midnight) and €70 at night (from midnight to 5 am), negotiable. The taxi rank is located between exits 2 and 3 of the airport. This means of transport offers the advantage of taking you exactly to the entrance of Piraeus corresponding to your ferry. The port is very large and walking long distances under the sun with luggage can be tiring.
Train
The journey takes about 1 hour, the cost for a one-way ticket is €10, €7.50 for over 65s, and free for children under 6 years old. Trains run hourly from 6 am to 10 pm. The train station is next to the metro station, and tickets are purchased at the station. The arrival in Piraeus is in front of the ferry docks.
Metro
The journey takes about 1 hour but currently requires two changes along the way: you start at the airport with Line 3 (blue) and change at Doukissa Plakentias, still on Line 3 (blue), then change again at Monastiraki station, taking Line 1 (green) to Piraeus. The cost is €10 (free for children under 6), the frequency is every 30 minutes from 6:30 am to 11:30 pm. The metro station is outside the airport in a building where tickets are purchased on the first floor, then you go down to reach the platforms. Remember that the Monastiraki stop is right in the center of Athens, so if you're not in a hurry to reach the port, you might consider spending a few hours in the city. The arrival in Piraeus is in front of the ferry docks.
Bus
The bus line to take is the X96 of the OASA transport company (Peiraias - Athens Airport Express), with a frequency of 20 minutes during the day and 40 minutes at night, costing €6 (€3 for over 65s and free for children under 6). The journey takes about 90 minutes. Tickets can be purchased at the information kiosk outside the airport or directly on the bus, and the stop is in front of the Arrivals area (for the return in front of the Departures area). Buses on this line run every day and at all hours. The arrival in Piraeus is in front of the ferry docks.