You can take the BUS X96(A) from the Piraeus
central train station Start point
ΣΤΑΘΜΟΣ ΗΣΑΠ -> ΑΕΡ/ΝΑΣ ΑΘΗΝΩΝ(EXPRESS) (Station ISAP -> Airport Athens(EXPRESS).
Stop Point: ΠΛ.ΓΛΥΦΑΔΑΣ (PL.GLYFADAS)
The ticket cost 0.80 euro aka 7.5 :- and you can reused for all the public transportation vehicles for about one and half hour.
For more info you can use this site
http://www.thesa.gr/oasa/index.asp but unfortunately it will be all Greek for you.
Greetings from the melting down Athens.
Do kan ta busen X96(A) avlägsna sig från Piraeus central törget stationen (Stationen ISAP -> flygplatsen Athens(EXPRESS) till torget Glyfada.
biljetten kostar 7.5 sek.
Good Luck.