Kardamaina (Greek: Καρδάμαινα), is a small Greek town 7 km from Kos Island International Airport at Antimacheia, situated mid-way along the south coast of the island of Kos. It lies in the municipal unit of Irakleides, in the Dodecanese. Once a small fishing village, it is now a popular summer destination over the past two decades, offering pubs and restaurants, bars and night clubs and watersports facilities. There are 1,650 inhabitants at the 2011 census with a land area of 35.150 km². Between June and September the town population may triple due to tourist influx.
Kardamaina is built on the site an ancient Alasarna settlement. During the 2nd century BC, Alasarna was an important urban center with a thousand citizens (excluding slaves).
The archaeological excavations have brought to light some impressive ruins such as a temple of Apollo, an extensive Early Christian settlement (from the few known in Greece), and four basilicas that belong to the same period. Stone objects of everyday use (millstones, tools, vases, vessels), mostly made of volcanic and sedimentary rocks have been recovered.