Ferry to Mykonos

From the airport, you can access two ports that service Mykonos, Piraeus, the main port for Athens, or Rafina. I think that Piraeus would have more options for ferry types and frequencies. I am not sure if good ferry schedules are available yet, but you can try a search, look at Ferries.gr or several other sites that pop up on a search. The main difference between ferries are speed(and cost) From the slow car ferries, to the large Catamarans, to the fast catamarans and hydrofoils. My preference is the large Catamarans, big enough to be stable, fast enough to get you there, and dependable in a variety of weather conditions. However, for your needs what boat gets you there on time is the one to take. Tickets can probably be had at the airport, otherwise from any agency as you get off the train at Piraeus. Another option you did not mention is flying, both Aegean Air and Olympic offer reasonable priced budget flights to Mykonos.

Actually, there is an Airport Express bus to Rafina that leaves frequently, and there are several ferries from Rafina to Mykonos that take as little as 2 hours. Rafina is closer to the airport and easier to reach.

You can purchase ferry tickets at the airport from Amphitrion Holidays in the Main Hall between Exit/Entry doors 2&3. They're open 24/7. If you want to purchase them in advance go to the AH website so you can just go to their office at the airport to pick them up. The online purchase fee is only 2 euro. Catch the bus from outside door 5.

Here's a link to the Rafina>Mykonos ferries for June 27: http://www.tinyurl.com/dgvou9

The first highspeed departure is at 7:40am on the Seajet2.

"Pyros?" No such island. Do you mean Paros or Paphos or Patmos?

I agree with Paul's suggestion about flying. You're already at the airport, so just stay there, instead of going through the bother of transferring to Piraeus, then trying to find the dock that your ship is at (there are several).