Owing to sudden changes, it's difficult to get advance information on ferry schedules. Port Authority offices have the most recent ferry schedule information, and the Greek Travel Pages website (www.gtp.gr) and Ferries.gr (www.ferries.gr) are also helpful.
Ferries between any of the Northern Aegean islands and Piraeus, Athens's port, take 8 to 11 hours (Piraeus–Samos, approximately €45).
There is one daily overnight ferry from Piraeus to Lesvos, except Saturday (€43, 10–11 hrs); there is only one weekly ferry from Thessaloniki to Lesvos (€38, 16 hrs). These ferries call at Chios first (€38, 8–9 hrs).
Five to nine ferries travel each week from Piraeus to Samos (€39, 15 hrs), arriving in either Samos town or Karlovassi (28 km [17 miles] northwest of Samos town), some stopping at Syros, Mykonos, and Evdilos/Ikaria.
Ferries and hydrofoils to Kusadasi, on the Turkish coast, leave from Samos town.
As for service between the various Northern Aegean islands, there is daily service between Lesvos and Chios. The regular ferry costs €19.50 and takes 2½ hours. There can be as many as three ferries per week between Lesvos or Chios and Samos (7 hours from Lesvos, €18; 3 hours from Chios, €13).
Chios Port Authority (22710/44433; 22710/44434 in Chios town.)
Mytilini Port Authority (22510/40827 in Mytilini; 22510/37447; 22510/24115.)
Piraeus Port Authority (210/455–0000 or 210/455–0100. www.olp.gr.)
Samos Port Authority (22730/27318 in Samos town; 22730/30888 in Karlovassi; 22730/61225 in Pythagorio.)