Because of Iceland’s abundant volcanic activity which includes about 100 dormant and 30 active volcanoes, there is also an abundance of geothermal water.

There is evidence of this geothermal water being used for bathing by Icelanders as far back as 1200; the first mentioned hot pool is Snorralaug, or Snorri’s Pool, after Snorri Sturluson (1170 - 1241) the foremost preserver of Norse cultural heritage. Although Snorralaug is preserved in Reykholt, West Iceland, and is no longer in use, there are many other hot pools to be found in the landscape.
Large or small, rich or poor: Almost every town has own public swimming pool with at least one geothermal hot pot. The public hot pot is part of the daily life of many Icelanders and is a place of socialization, the well known “pottamenning” — hot pot culture. Of these public pools and natural hot pots, a few in different parts of the country are worth mentioning for their incredible vistas. 
Where the road ends: Krossneslaug at Strandir 
In the Westfjords village of Norðurfjörður, Krossneslaug appears to extend right into the ocean where it is perched on the edge of a high overlook. Some have reported even seeing whales from the pool. Another pool that gives a more raw experience of a geothermal pool is Hellulaug located in the southern part of Vatnsfjörður close to Flókalundur. While there are no changing facilities, there is no entrance fee either. From the small pool, one side of which is a rock wall, there is a path down to the beach which you can also observe from the pool. 
The Blue Lagoon of the North: Jarðböðin at Mývatn 
In North Iceland, Hofsós swimming pool in the village of Hofsós also offers incredible panoramic views of the fjord. Also located in the North is Mývatn Nature Baths, commonly called the Blue Lagoon of the North as the water is the same pearly blue colour, however Mývatn has far fewer visitors and is much more remote. 
East Iceland’s hidden gem: Selárdalslaug 
In East Iceland, the Selárdalur swimming pool located close to Vopnafjörður is nestled against the Selá river in a ravine between two mountain ridges. Built in 1949, the pool is next to a hot spring from which the pool receives its water. 
Follow the locals in Reykjavik: Visit the beach in zero degrees 
In West Iceland, the geothermal beach of Nauthólsvík in Reykjavik offers the chance to both soak in a hot pot on the shore as well as swim in the open ocean in temperatures warmed by geothermal water. This is a great place to try sea-swimming as you can quickly and easily warm up. Located close to Reykholt, the home of Snorralaug, the geothermal area of Deildartunguhver feeds Iceland’s newest natural geothermal space, Krauma. On a family farm and situated amongst greenhouses with a mountain backdrop, Krauma offers a natural geothermal spa that includes hot pools of varying temperatures as well as a meditation room with a wood-burning stove.