Kythnos Thermal Spa

Kythnos belongs to the western Cyclades and lies between the islands of Kea and Serifos. It is also called Thermia due to the thermal springs located on the northeast side of the island, in the picturesque bay of Loutra. The Kythnos Thermal Spa occupies an area of 6,200 square meters. Decree No. 244/2013 of the Athens Administrative Court of Appeal (Government Gazette 3025/Β/28.11.2013) transferred full ownership to HRADF and by Law 4389/2016 the Kythnos Thermal Spa is included in the properties listed in Annex C, which remain the property of HRADF.


The facilities of the Kythnos Thermal Spa include:

  • Hydrotherapy, room with 14 individual marble baths and a hydro-massage tub
  • Water sports facilities, including 3 wooden huts and a platform for accommodating athletes and beginners
  • Xenia Hotel (out of order)

History of the Kythnos Thermal Spa

The first spa tourism infrastructure in Greece was built on Kythnos, during the reign of King Otto I and his queen Amalia around 1840. It is said that Queen Amalia brought from Bavaria some of the leading doctors of the time to treat her infertility. Bavarian doctors of the period had extensive experience in hydrotherapy, already widely used in central Europe in the 19th Century, and the queens’ doctors searched Greece for therapeutic springs to treat the young queen. They decided that the healing springs of Kythnos would be ideal for the treatment of infertility.

As a result, there are still marble baths, at the Hydrotherapy Center, that were designed for the royal couple.

The reservoir of the spring of Agioi Anargyroi was built in 1838 after chemical analyses were first carried out to establish the therapeutic properties of the springs. In 1836, the architect Christian Hansen arrived in Kythnos and made the designs for the spa complex with his assistant Laurent. Eventually the project was completed by Laurent.

The Hydrotherapy Center was built in 1857. The adjacent neoclassical building with a tiled roof was later built by Ernst Ziller.

Properties of the thermal spring water of Kythnos

There are two thermal springs in Kythnos. Agioi Anargyroi (recognition as a therapeutic spring: Government Gazette 1860/N/24.6.2016) is saline and is located in the adjacent old building. The Agioi Anargyroi Spring has a temperature of 40.5º Celsius, and is characterized as superheated, weakly carbonated, weakly radioactive and hypertonic, with a high chlorinate content and low levels of sulphide.

Kakavos Spring (recognition as a therapeutic spring: Government Gazette 1861/B/24.6.2016) is loicated 50 meters away the first and has a temperature of 52.5º Celsius. The spring water is characterized as a superheated, weakly carbonated, weakly radioactive and hypertonic, with a high chlorinate content and low levels of sulphide.

The spring water is recommended for:

  • Musculoskeletal disorders, especially rheumatoid arthritis
  • Nervous system disorders
  • Skin diseases
  • Gynecological disorders

Hydrotherapy is recommended for systemic, communicable and malignant diseases, liver and kidney failure.