Greece has always been known for its islands and, although several do have airports and can be reached by air, many are still accessible only by ferry or hydrofoil, especially if you are traveling with a car. Major improvements have been made over the past five years and modern and faster ferries have been introduced. Certain journeys that once took up to 12 hours can now be completed in less than six. However, fares on high speed ferries and hydrofoils are more expensive than the older, traditional ferries and they do have the disadvantage of being more cramped as the seating is similar to that on an aircraft and you cannot move around outside. It should also be noted that these vessels have to drop their speed during gales and adverse weather conditions and also when nearing coastal areas that may be affected by the vessel's wash; this can make the journey very tedious.

Ferry and hydrofoil sailings to the islands vary throughout the year. The majority of vessels depart from Piraeus whilst others leave from Rafina and other ports as listed below. Smaller hydrofoils to islands such as Aegina, Poros, Hydra and Spetses leave from Zea Marina in Piraeus, which can be reached by bus no 905, or trolley no 20 eastbound from Piraeus metro suburban train station.

Tickets can be bought from travel agents or at the port of departure. It is advisable if you are taking a car and/or require a cabin, to book in advance, particularly at the height of the summer season and on Friday evenings. Tickets are booked one way - you purchase your return ticket once you arrive at your destination. If you are travelling to an island for the weekend in summertime, book your return immediately on arrival; Sunday nights can be very busy.