You will be able to see more of Greece along the way and save time and money if plan your travel to and within Greece as part of a larger itinerary.
If Greece is your only destination it s a bit different with Athens being the overwhelmingly most popular choice.
Entering Greece: the very means of transport one uses to will influence what one will be able to see and may help avoid unnecessary back tracking to major transportation hubs such as Athens or Piraeus.
Sooner or later you'll want to get to Athens perhaps, but on the way, why not see some of the ancient treasures of Greece without going to Athens first?
Via ferry from Italy for example, travelers entering Greece have the option to go directly to the Greek mainland (either to central Greece from Igoumanitsa near Corfu or to the Peloponnese from Patras) without going to Athens first.
From Across Corfu (Kerkyra) at port Igoumanitsa, there are several major sites you could visit en-route to Athens and beyond. These include Dodona, Meteora, Ossios Lukas and Thebes.
From Patras you could travel to the major sites of the Peloponnese such as Olympia, Epidavros and Mycenaea and then continue on to Crete via Gythion (ferry schedules permitting). From Crete you could fly or ferry to many islands and the mainland.
Travelers heading for the Balkans or Ports on Northern Italy's Adriatic coast might want to explore the ferry, train and bus schedules available to them.
If coming from central Europe and the Balkans overland, explore the car hire options and train routes and tour Northern and central Greece on your way to the islands. From Thessaloniki, one can, in summer at least, ferry to the central Cyclades and from Kavala in near by Thrace reach the islands of Thassos and Samothrace.
Travelers already in Northern Europe and the U. K. have many options to consider as their way to enter Greece. If already in Europe you definitely should consider some of these alternatives to a direct flight to Athens International Airport (ATH).