You can go to Irakia by boat from the port of Piraeus through line Kithnos – Iraklia – Schinoussa – Koufonisia – Amorgos – Thira – Ios – Folegandros – Milos, and through the line Paros – Naxos – Iraklia – Schinloussa – Koufonisia – Katapola.
For more information:
PORT AUTHORITIES OF PIRAEUS 2104226000
PORT AUTHORITIES OF NAXOS 22850 22300