Transportation from Athens (Greece) to Sifnos (Cyclades)
Ferries for Sifnos leave from Athens’ port Piraeus.
Getting to Piraeus from Athens’ center: you can find info on bus, metro, taxi, below
https://www.ferriesingreece.com/ferries-ports-athens.htm
Getting to Piraeus directly from the Internation Aiport “Eleftherios Venizelos”
by bus:
This is the only direct means for this route. There is one bus line, named X96, running directly from Athens airport to Piraeus port (final stop). This bus runs 24/7 and departs every 15-30 minutes. Tickets cost 5€ and the journey is 90 minutes.
You can find the bus stand directly outside of the arrivals gate, between exits 4 and 5.
Keep in mind that during rush hours there is high traffic, the ride can take up to 2 hours
You can download the bus timetable in the pdf below:
https://www.welcomepickups.com/wp-content/uploads/2017/02/X96-Athens-Airport-Bus-to-Piraeus-Port.pdf
by metro:
This route involves one change and takes approximately 1 hour. First, you need to take the blue line heading towards Agia Marina and get off at Monastiraki station; there interchange to take the green line towards Piraeus Station. The ticket for this route costs 8€. You only need to validate this ticket once, when entering the Metro station at the airport. For more information in regards to using the Metro, visit
http://www.stasy.gr/index.php?id=1&L=1
by suburban rail
This route involves one change and takes approximately 1 hour. Take the suburban railway which heads towards Ano Liosia and get off at Neratziotissa; there you need to interchange by taking the green metro line towards Piraeus Station, as above.
The ticket is the same as for the Metro and costs 8€. You also validate it by using the same machines as for the Metro.
by taxi:
Taxis are readily available outside of the arrivals terminal at Athens Airport. You can find a taxi 24/7 for 54-70€ and the ride is about 45’. You can pre-book a taxi with English-speaking driver with Welcome Pickups.
https://www.welcomepickups.com/athens/airport-transfer-book/
From Piraeus Port to Sifnos
There are many ferries traveling from Piraeus (departure port) to Sifnos (arrival port).
There are 2 types of ferries. The fast Ferries are usually smaller and cannot carry cars. The larger ferries can carry your car but take twice as long to travel.
Ferry information can be found in the tabs of this website
Tickets can be bought directly at Piraeus Port, but you should book them ASAP online since they can get sold out quickly, months before your travel.
The trip from Athens to Sifnos takes approximately ~3 hours, thus one should not plan a day-trip to the island but plan at least 1 overnight stay or more.