This is an article that the Greek News Agenda has published about hiking on Greek islands; it is called hiking Greek islands: explore off-the-beaten track treasures!
The Greek islands, well known for their sunny beaches and clear blue waters, attract outdoor enthusiasts not only for activities such as diving, scuba diving, snorkeling, wind surfing, sailing or just sun bathing, but also for hiking and walking tours! Walking tourism has been gaining ground in the past few years, thanks to public and private initiatives sign-posting routes, publishing maps, organizing walking tours and operating special sites to inform people about available paths and walking tours. This form of tourism is particularly well suited to the Greek islands due to their mountainous morphology and stunning vistas to the endless blue. But there is more to explore; walking tours often include stops at archeological sites, spots of geological, natural, or architectural interest, deserted villages, wineries, artist’s galleries and more!
The rest of the article is here; hiking on Greek islands
Here is a video of the footpaths on Kefalonia.
Footpaths on Kefalonia