The abundant hot springs are another special feature of Nisyros. At many points along the coast of the island, hot water flows at temperatures ranging from 30 to 61 degrees. It involves mixing sea and rain water with the geothermal fluids of the upper hot horizon. These, warm and lighter, manage to get close to the surface following the great cracks and cracks in the area.
The most famous of the hot springs are those of Loutra, 1500 meters north of Mandraki, and Thermia, next to the church of Panagia Thermia, on the northern edge of the village of Palon. Both are classified as 'thermal hydrosulfurized algae'.
The source of Thermia is known from antiquity. The inscription found in the ruins of the great portico of Roman baths operating in the same area, "Olivian only in the midst of Hippocrates of the wounded diseases of sickness" (Happy the man who will do so, ] The merciful (olive tree) threshold of Hippocrates' baths [rinsing] the harmful diseases) reinforces the view that the father of medicine Hippocrates had chosen this source of Nisyros as a healing spa center.On the same source probably refers to Buonde Lmonti as healing baths:
      Ad trionem in the montis, contigua maris, constiguous consisted, ad quam circumstantes, doloribus oppressi, accedunt, et morti, in patriam incolumes reventuntur
On the nearby shore, on the outskirts of the mountain, there is a cave where sufferers of pain come to heal, stay for a while and then leave healthy.
The last period of operation of the treatment center in the area is from 1895 until the early 30's, the well-known "Loutra Pantelidis".

Today, the old baths have been restored, but they are not yet ready to work. The source temperature is 33 degrees, but it is expected to increase by 8-10 degrees if the water is pumped.
The waters of the hot spring of Loutra have been taking advantage of the Municipal Baths of Mandraki since 1872. Its healing properties are known for rheumatism, arthropathies, skin diseases and circulatory system diseases. The maximum source temperature is 46 degrees.
A third well-known hot spring is in the bay of Avlaki. Its waters had been used for spa treatments before the settlement was abandoned. Hot water is now spilling into the sea and its maximum temperature is 61 degrees.
In addition to the hot springs, Nisyros has many places where hot steam rises. Two of these sites have been used in the past as natural saunas. The main one, known from antiquity, is in the place of Fire, where the chamber of the steam baths and adjoining auxiliary buildings of the baths is still preserved. The other location is at the entrance of Emborios settlement. The vapor temperature is 34-35 ° C.