There are endless options for how you can make the 30 minute journey into the city centre from the airport; the metro is cheapest at €6 each way with a taxi costing €70 round trip.
We chose to only purchase a 24 hour Athens line ticket for €16.20 each and forgo the Piraeus line, as the main attractions we wanted to see were dotted along the Athens line map.
Between November and March tickets for the main attractions like the Acropolis, Panathenaic Stadium and the Temple of Poseidon range between €4 and €10.
At €15 for 15 minutes of racing, it’s worth the 25 minute journey from the city centre.