The abundant thermal springs constitute another characteristic feature of the island of Nisyros. Along the island's beachside and in several places hot water is welling out (starting from 30 to 60 degrees). It's about a combination of sea water and rain water containing geothermal liquids of the superior thermal horizon.

The most famous springs are the following: the one of Loutra at 1500 metres in the north part of Ìandraki and the one of Thermiani, in the northern border of the village of Paloi. Both of them belong to the "salty thermal springs containing sulphurated hydrogen".

A third famous thermal spring is the one of Avlaki.