This grouping of 12 (dodeka) islands (plus about 150 smaller islands) in the southeast Aegean is one of Greece's most popular holiday destinations for a taste of authentic Greek island life. In all, 26 of the islands are inhabited, but the largest and most populous 12 give this grouping its name. Being the most southerly island group of the Greek Aegean Islands, the tourist season begins in May and stretches on into October, with the largest crowds showing up in July and August.
Let's briefly look at these 12 islands one by one, in no particular order, hitting their high points. Unless otherwise mentioned, all of these islands feature fantastic beaches.
First in importance, and first in size, Rhodes also serves as the capital of the group. Historically, for thousands of years, whoever controlled Rhodes controlled the entire archipelago of 12. Rhodes has the largest, best-preserved medieval city in the world in Rhodes Old town, no lack of archeological sites, and some of the Med's most beautiful beaches all around its perimeter. The island was once a confederation of 3 important city-states which banded together to form a cohesive political power in 300 BC which dominated the region for centuries.
Kos, home of Hippocrates, Father of Medicine,is the most fertile of the 12,and is unusually rich in archeological sites. Kos used to be flooded in high season with package tours, but they have dropped off somewhat and one can find bargains now. Not as hilly as the other islands, Kos is ideal for bicycle travel. Day trips to Bodrun, Turkey are available, as well as excursion to nearby islets.
Karpathos and Kasos, close to Crete, have developed more slowly and much of both islands is unspoiled. These are not party islands, but rather places to come and learn about a vanishing way of life many centuries old.
Nisyros features buildings made of volcanic stones in its capital of Mandraki, with a town beach of black sand. It's a volcanic island, featuring stunning hiking tours around the volcano's caldera.
Patmos, best known as the exile island of the Apostle John, where he received and wrote down the last book of the Bible, Revelation, is also an excellent beach island. The Monastery of St. John the Theologian, built around the cave where the apostle is said to have lived, is a highlight.
Kalymnos is famous for its sponge fishermen, many of whom have emigrated to Tarpon Springs, Florida, the highest percentage of Greeks of any town in the US. Kalymnos is also famous as a center for rock climbers. Visitors rave about the cheap room prices and the beautiful sunsets.
Halki, close to Kalymnos and also a center for sponges before they died out, is so small it has no cars. A favorite for package tours looking for an uncrowded island.
Astypalea, off to the west of the other islands, has a more Cycladic feel, with its cubic white cottages. A favorite of Greeks, it's really two small, isthmus-connected islands. Very uncrowded.
Kastellorizo has no beaches, but many rocky coves ideal for snorkelers.
Leros has, in its main town, Laki, many beautiful Art Deco buildings designed by Italian architects during the reign of Mussolini, who'd wished to retire in Rhodes.
Symi's capital, Symi Townhas the best natural harbor of the Dodecanese. The town is like an amphitheatre, with tiers of neoclassical mansions rising to the castle on its heights.
Tilos, between Kos and Rhodes, has uncrowded beaches, deserted villages, beach camping, and lots of good hiking. Tilos has banned bird hunting and the island has become a sanctuary for migrating flocks.