There is no airport on Thassos. Every version of this journey is overland to the coast east of Thessaloniki, then a short car ferry across.
The crossing
Car ferry from Keramoti, near Kavala airport, in about 35 minutes. There is also a crossing from Kavala itself, which takes rather longer.
Keramoti is the short one and the one to aim for if you are driving out from Thessaloniki anyway. Kavala is the one that makes sense if you are already in the city or flying into Kavala airport for the trip.
Ferry frequencies change by season. Check the current sailings with the operator before you commit to a crossing time, especially outside summer - that is the one number on this route that nobody can print usefully in advance.
Take the car
The point of Thassos is the ring road. It is the greenest of the north Aegean islands, with white marble quarries, mountain villages inland and sandy beaches strung around a coast you drive.
A car helps a great deal here, and since this is a car ferry on a short crossing, bringing your own or your hire car is far simpler than arranging something on the far side. Renting a car in Greece covers what to check before you take a hire car on a ferry, which is worth doing.
What is at the other end
Four or five nights if you want the coast and the interior. It also works as a week for people who want a beach holiday with somewhere to drive.
The island splits into a coast and a cooler interior: Panagia, Potamia and Theologos sit inland with slate roofs and plane trees, and are noticeably cooler than the shore. On the coast, Saliara - Marble Beach - is a small cove on the north-east where the shore is ground white marble rather than sand, reached down a rough track.
Our Thassos guide has the practicalities, things to do in Thassos covers the quarries and the villages, and the beaches cover the ring road’s coast.
If you are coming the other way
This route also works as an extension of a Thessaloniki trip rather than a destination in itself. Day trips from Thessaloniki is honest about which northern trips a single day can hold - and Thassos is not one of them. It is a stay, not a day out.