Built in the north-east of Kythnos, Loutra (the Baths) have been inhabited since ancient times due to the existence of drinking water and the natural harbor. Considered the seaport of Hora just 5 km from it and 11 km from the port of Merichas. Loutra (the Baths) are among the most famous places of spa tourism in the Cyclades, but also throughout Greece. It is the fourth most populated settlement with 81 permanent inhabitants according to the last census and it is mostly engaged in tourism and fishing.
The spa is famous for its thermal sources, known since antiquity as there have been finds from digs in the region. In later years two chemical analyses ordered by King Otto and queen Amalia, one in 1830 and another in 1833, highlighted the health properties of the water sources. It is said that the Queen pressed the scientific investigations due to gynecological complications. Although no solution to the problem was found, Amalia who especially loved Kythnos and the Baths visited quite often over the years. Today the preserved marble baths created for the bath befits a royal couple.
Due to the hot springs the older name of the island Thermia is derived and it is used even today. Many people (mostly elderly and people with arthritic problems, muscle and neurological problems) arrive at the island choosing the area of Loutra (the Baths) for their summer vacation for this reason.
The Spas of Kythnos include a spa unit with hydromassage & 14 baths all belonging to the EOT (The Hellenic Tourism Organisation). Swimming outside the premises EOT is possible specifically at the point the waters of the springs flows into a natural sea pool flowing into the sea where hot waters are joined by the cool sea. The thermal waters of the Baths which gush out of the source into the sea are very warm and some areas are characterized extreemely hot. There are two main sources with the characteristics of mineral waters: the source of Kakavos with mainly ferrous lightly radioactive water with temperature 52 ° C and the source of Saint Anargyri with mostly saline medium level radioactive water with a temperature of 38 ° C.
Nowadays the Baths are particularly well developed for tourism, since apart from the tourist spa infrastructure, they are also close to small beaches (Agia Irini Schinari, Agios Sostis and Potamia) and also offer an organized port with marina for sailboats and other pleasure craft. Hotels, apartments, restaurants and ouzo bars are plentiful in the village of Loutra. There are also businesses that cater to car rental & scooters, diving school, a bakery and a super market that serve the needs of the region.
From the Loutra (the Baths) the islands of Syros and Gyaros can be seen clearly on the horizon as they expand to the east of the island. This sea to these islands is considered especially "difficult" by many sailors as it is also affected by the sea currents of "Cavo Doro". Thus, the port of Loutra is especially useful for small boats as is the northernmost port of the island thus providing the most welcome haven in cases of bad weather.