Greece is generally not crowded during December, as it's considered the off-season for tourism. The colder temperatures and the approach of winter deter many tourists from visiting, resulting in fewer crowds at popular attractions and destinations.
Is Santorini crowded in December?
The crowds, though, are most certainly gone, and this month you can enjoy the island in its authentic state: try a quiet coastal hike alongside a huge volcanic caldera, dine in one of the excellent local restaurants, explore Santorini's history at museums and archaeological sites, and sample native wines at one of many …
Should I go to Athens in December?
Festive Spirit – The Christmas spirit takes over Athens, much like the rest of the world, in December. It is an amazing time to visit Athens as you will get a sneak-peek into the unique Christmas traditions of Greece and relish the local Christmas treats that are not available at any other time of the year.