Usually, the cheapest flights are with Aegean Air or Easyjet. Lufthansa is often the cheapest of the major airlines: use an aggregation service such as Opodo.com or Kayak.com to search for cheap flights after looking at www.easyjet.com and http://en.aegeanair.com/ .

The Greek ferry system is a wonder and a delight.

Timetables are basically secret (not intentionally, just due to inefficiency); however our charterer Greek Sails has got hold of the Easter 2010 timetable for some relevant ferries for us.

Note that Hydrofoils (known as "Dolphins") are twice as expensive but are twice as fast as the much-larger car ferries. For other islands in he Cyclades, there are also "Fast Cats" which are nearly as fast as hydrofoils and also as cheap as car ferries.

The car ferry between Pireaus and Poros stops at Poros in the Mid Season (which this is), to get to and from Hydra and Spetses you have to take a dolphin.

If we all get to Poros early on Friday 9th, we could possibly sail off that evening; but that is a bit unlikely.

All internet links to ferry timetables eventually take you to the same  system
http://paleologos.forth-crs.gr/english/npgres.exe?PM=BO#RoutesTable
which doesn't work.

This list doesnt include the Poros/Hydra/Spetses line http://www.greekislandhopping.com/Home/Homefr.htm

This will still be low season, so for people needing to get an earlier flight  from Spetses, it may be only hydrofoils to Athens, and no ferries. These are faster but more expensive.
http://www.spetsesdirect.com/getting_to_spetses_in_brief

When we meet up at the beginning of the trip in Poros afternoon, then we buy our return tickets (before the ferry shop shuts). Getting advance timetables is like pulling teeth.


Alternatively we could come back via Lavrio(n), on the Attic peninsular, and early departers can get a *bus* to the airport from there.
http://www.athensguide.com/lavrion/

Ferry Ports of Rafina  and Lavrion

A bus route linking the Athens International Airport at Spata to the port of
Rafina in eastern Attica will be operated by the KTEL intercity bus system
and will be called "Athens Airport-Rafina Port." It will function daily from
6 a.m. to 9.20 p.m. with buses leaving every 40 minutes and making a stop in
the seaside resort of Loutsa. There are also regional buses to Lavrion,
Markopoulos, Keretea and Kalyvia. Buses depart from the Arrivals Level
(close to Door 3) of Athens International Airport. Ticket prices for one-way
trip is ?3 for all services except for the port of Lavrio (?4).


Arriving buses disembark passengers at the designated area of the departure
level of the Main Terminal Building. They are orange.

(Just a note about the Rafina buses from the airport - they depart not from
near Arrivals Gate 3 but across that road and about 100 metres along the
outer access road, to the left, the bus stop being right opposite the
Sofitel hotel near the foot of an outside staircase.  Unfortunately the
walking route is not signposted.  Also worth noting that the ticket booth
for the Athens buses does not sell tickets for Rafina - you just pay your 3
euros on the Rafina bus.

A point for the return journey - the bus stop adjacent to the square/plateia
in Rafina is only served by the Athens buses.  If you want the airport bus
you must descend the steps to the port road at the other (seaside) end of
the square and the shamefully graffitied and damaged bus stop next to a
little newspaper shop is where the airport bus picks you up as it leaves the
port.)

http://www.athensguide.com/airport.html

Athens Suburban Buses
BUS TERMINAL: Mavromateon St., Areos Park. Easy to walk to from Omonia
Square. Just three blocks past the Archaeological Museum on 28th
October-Patission Street. These fares have gone up another 30 to 50%.

AMFIARAIO (KALAMOS): Tel: 010 8230179
05.45, 06.30, 08.00, 09.45, 11.30, 12.45, 14.30, 16.30, 19.00 Fare: 2,64 ?.

MARATHONAS: Tel: 010 8210872
06.00, 06.50, 07.30, 08.15 from 09.00 to 13.00 every 30', from 13.00 to
21.00 every 60´,22.30 Fare: 2,35 ?.

NEA MAKRI: Tel: 010 8210872
05.30, 06.00, 06.15, 06.50, 07.30, 08.15, from 09.00 to 17.00 every 30',
from 17.00 to 21.00 every 60´, 21.45, 22.30 (only in Summer) Fare: 1,91 ?.

PORTO RAFTI: Tel: 010 8230179
from 05.45 to 19.45 every 60' Fare: 2,35 ?.

RAMNOUS (SOULI): Tel: 010 8210872
06.00, 08.15, 10.00, 12.30, 15.30, 19.00 Fare: 3,23 ?.

SOUNIO (via coast road): Tel: 010 8213203
from 06.30 to 17.30 every 60´ Fare: 3,96 ?. (one can also take this bus from
Klafthmonos Sq., or Filellinon St.).

SOUNIO (via Lavrio): From 05.45 to 17.45 every 30', 18.45, 19.45, 20.30,
21.30 Fare: 3,67 ?.

SOUNIO - ATHENS: From 06.00 to 20.00 every 30'.

http://www.athensguide.com/practicalinfo/suburbanbuses.htm