Antimachia Castle Kos is located on a hill near the village of Antimachia, about 24 kilometers southeast of Kos Town. This strategic position offers breathtaking views of the Aegean Sea and the surrounding landscape. Due to its location, the castle controlled important sea routes between Kos and Nisyros.

The construction of the castle began in 1337 by the Knights Hospitaller. They built the fortress to protect the area and to maintain control over trade. Over time, the castle underwent several changes. After an earthquake in 1493, Grand Master Pierre d’Aubusson ordered extensive repairs. Consequently, a large semicircular bastion was added at the northwest entrance, strengthening its defenses.

The castle is designed with a triangular layout, and each side is fortified to adapt to the natural terrain. The entrance features the engraved arms of the Grand Master, marking the 1494 restoration. Inside the castle, visitors will find several ruins, including cisterns and two churches. One of the churches, the Church of Agios Nikolaos, dates back to the 16th century. 

Notably, Antimachia Castle was once home to a small settlement, which was abandoned in 1840. As a result, visitors can explore the ruins of this ancient village, adding a sense of mystery and depth to the visit.

The castle is easily accessible by car or motorcycle. It lies along the main road connecting Kos Town with the southern parts of the island. For convenience, it is open daily from 8:30 AM to 4:00 PM, except on Tuesdays. Entry to the castle is free for all visitors. To avoid the midday heat and crowds, it is best to visit either in the early morning or late afternoon.

In conclusion, Antimachia Castle Kos offers a unique blend of history, architecture, and stunning views.