Sar'e Ein
This is a really tourist town 29 km to the west of Ardabil. It is one of the most important hot spring spa centers in Iran and the world, annually attracting more than 1,500,000 visitors coming to use its 9 spas with therapeutic . A taxi driver can take you to one of theses hot springs around the Sar'e Ein village; otherwise, you will have to ask directions to find one.
The best would be to pay a marginally higher fee and use the cleaner and more modern "hydrotherapy Complex," the main baths in the village. Naturally, the baths are segregated, These can be used both by Iranians and foreigners, but foreigners are charged according to the length of their visit.