Agathonisi is the north most islet of the Dodecanese islands complex. The coast configurations of the island are quite impressive. There are many beautiful and windless bays as are: Hohlia, St. George, Poro and Maistro as well as their small promontories. The surface of the islet is comprised of rocky and barren hills. Areas appropriate for agriculture are very few indeed.

Water for the inhabitants is collected by way of rainwater cisterns that are filled by water carrying tankers in times of drought. The island of Agathonisi was named Yetousa in ancient times. According to contemporary researches today's name is the result of an etymological mistake from the plant from which the name is derived "Agathonisi", i.e. Island of the Thorns.

After the incorporation of the Dodecanese to the rest of Greece, the island fell under the jurisdiction of the municipality of Patmos of the province Kalymnos, with the name of "Agathonisi" or Gadaros-"Donkey" (because the shape of the island resembles a donkey galloping towards the river Maiandros). In 1953 it became a separate community and has remained so until today.

The quiet life on the island, the calm, the hospitality of the locals, the cleanliness of the beaches and the fresh fish which a visitor is able to enjoy, since the cooking is done according to traditional recipes, all make Agathonisi an ideal place for those who wish for quiet holidays away from the hustle and bustle of the main tourist routes.