Air
Even if they have the time, many people avoid the 8- to 10-hour ferry ride from Athens and fly, which takes less than an hour. Sky Express, Aegean Airways, and Olympic have at least a dozen flights a week (three or four daily) from Athens to Lesvos and Chios in summer and at least four daily flights to Samos. There are several flights a week from Chios to Lesvos, Limnos, Rhodes, and Thessaloniki; and several each week from Lesvos to Chios, Limnos, and Thessaloniki. From Samos there are several weekly flights to Limnos, Rhodes, and Thessaloniki; there are also flights (usually at least one per week) between Samos and the other northern islands, some operated by Sky Express. Check in online ahead of your flight; it's not uncommon for your seat to be sold to someone else if you choose to wait and check in at the airport instead.