The hot spring of Loutropoli Thermi has been used since ancient times for medicinal purposes. The temperature of the water is 49.9oC and shows a very high salinity which is due to the mixing of hydrothermal fluids with sea water.
The manifestation of the spring is the result of the intersection of two deep faults with directions SW – ENE and NW – SE which help the rise of underground water from great depths. A mixture of rainwater and seawater descends to the depths, where it is enriched in minerals and heated. Then through the faults it rises to shallow depths or even to the surface where it mixes again