SUMMER BY AIR
During the summer numerous charter flights descend on the island. You can book flights online or at most travel agents prices will vary as to the date you choose, usually you will find July and August the most expensive these are also the hottest months. If you don't mind the cooler days then May and October are much cheaper the weather can be wonderful but also there is the chance of rain and thunderstorms.
A few flights are now starting at the beginning of April.
There are also domestic flights from Athens.
SUMMER BY BOAT
If a drive/ferry holiday is to your taste then driving is an option. Allow three days to get here although it can be done in less if you have a couple of drivers and you don't mind driving through the night. The drive depending on your route will take you through France, Belgium, Luxemburg, Germany, Switzerland, Austria, Italy (there is no need to go through all these countries routes are many and varied taking either motorways or scenic routes). Log onto AA route finder website. The car ferries leave from Italy - Venice, Ancona or Brindisi. The most common seems to be the route from Ancona. The journey from Ancona (Italy) to Patras (Greek mainland) takes around 21 hours. There is the option of a cabin, an aircraft type seat or you can take a sleeping bag and find a spot on the deck. In summer this is a pleasant and a cheap option. The Ferries are very comfortable and include a disco, bars, cafe and restaurants, sometimes a small pool.
The journey takes you to mainland Greece the port of Patras. Once you arrive there it is an hours drive south to Killini where you get the local car ferry over to Zakynthos this takes around hour.