There is only one way to reach Thassos and this is done by boat. The port of Skala Prinos served by Kavala, the journey takes about 1 hour 30 min, and has about 5 imerisios routes during the summer.
The island has its own airport, but it is served by the airport of Kavala (Alexander the Great), which is just 17 kilometers from the port of Keramoti. Kavala mainly receives charter flights during the summer from all over Europe, but has twice daily connection to Athens International Airport. Alternatively from Thessaloniki, just two hours away from Kavala, It has international airport which also hosts many airlines. Renting a car is simple and the journey to Kavala / Keramoti is via Egnatia(E90). Alternatively, you can take the bus from Thessaloniki to Kavala every hour, the express route takes 2 hours normal 2,5.
According to the above, Thassos is near the Egnatia (E90), which is a freeway and interconnects throughout northern Greece. From Igoumenitsa on the west coast of the Ionian Sea to Alexandroupolis, and the east coast of the Aegean, near the Turkish border. The E90 has good links with southern Greece and all the Balkan countries.