Getting around GreeceIf you travel around mainland Greece, there’s a decent railway system which will suffice if you want to move along the main cities: it is very cheap, but certainly not one of the best in Europe. There’s also a comparably more expensive bus service, which covers more destinations. If you plan to travel a lot and want to be free to go wherever you want when you want, renting a car will be a good option.
If you want to go to the islands, the most convenient option will be to get to one of them by plane, and then using the extensive ferry system, that covers all of the Aegean sea. Depending on where you want go, though, island hopping can be easy and comfortable or take ages, since some islands are very close (the Cyclades, the Dodecanese), and others, like Crete, are very distant from everywhere else.