Your best option : pricecomparison website sush as Kayak, AirTickets or Skyscanner.
Up to you to try different dates to obtain the best prices.
Buying your air tickets 5 to 3 months in advance, the price range for a return ticket to Athens will cost you between 200 to 200 euros.
During the season, flights are operated by Aegean Airlines, Air France, Transavia, Alitalia or KLM airlines.
Outside the high season (from Nov. to Apr) there is no price variation. You will be able to book only through Air France, Alitalia and KLM.
[Beware : no direct flights to Paros for the time being from european cities, you will need to transit through Athens].
– By plane :
Flight duration :45 minutes
Return ticket for 140 euros (Aegean Airline, Olympic Air),
– By boat from the Pirea harbour :
To reach the port from the airport, take the X96 bus at the terminal exit. It is a direct Express route with Pirea as last stop. It will take you approximately 1 hour to reach the harbour and will cost you 5 euros.
The crossing will cost for an adult, without a car nor cabin, around 72€ for a return ticket and will last 3h45 or 2h30 by hydrospeed.
To ease your arrival, you may book your boat tickets directly on Internet with FILIPPIS TOURS or on the BLUE STAR FERRIES website. Tickets will be either sent by post or made available by the port offices.
For July and August, a one month in advance booking is sufficient. Outside these months, booking is unecessary as you will be ablr to buy your tickets directly and the port’s agencies.
Should you wish to visit the center of Athens first, take the X95 bus line.
To reach Pirea, take the underground green #1 line.