Krauma

You park beside Deildartunguhver, the hot spring that Krauma describes as the highest-volume spring in Europe, and watch boiling water pour out of the ground a few steps from the bath building. That water arrives at close to 100°C, is cooled through heat exchangers and mixed with glacial water, and fills five hot pools and one cold one without added disinfectants. Pool temperatures are not published, so expect a range from mild to quite hot.

A relaxation room with loungers and a fireplace, a steam bath and a restaurant using local produce round it out. Adults pay 7,900 ISK and children under 12 just 500 ISK, which makes it one of the better-value developed spas for families. It is about half an hour inland from Borgarnes and fits into a day with Reykholt and the Hraunfossar waterfalls.

Shower without a swimsuit before entering. The honest downside: the pools are compact and the setting is a farm valley rather than dramatic scenery, so it is more about the water than the view.