All year long there are daily scheduled flights from Athens International Airport "El Venizelos" to the airports of Heraklion, Chania and Sitia. Also during touristic season (April to November) charter flights from abroad arrive to all Cretan airports.
Daily routes link the port of Piraeus with the ports of Heraklion, Chania and Agios Nikolaos, while the island have direct ship routes to several Aegean islands (Santorini, Milos, Kythira, etc).
You can use Agia Galini Transport Services for group transport to Agia Galini and back to Ports and Airports.
The intercity public bus connects Agia Galini with all major cities in Crete the other prefectures. Here you will find helpful information on Intercity Buses routes here: http://gogalini.com/agia-galini-bus-routes-2014
There are Taxi services that you can book for your transportation.
Check the car rental services