Grettislaug

You follow a gravel road along the Reykjaströnd coast until it ends at Reykir farm, where two stone-built pools sit just above a pebble beach facing the island of Drangey. The oval pool, Grettislaug, is the larger and warmer one, about 4.5 by 4 meters and 80 cm deep, and holds 15 to 20 people; the round Jarlslaug holds five or six. Guides put the water around 39°C, sometimes up to 42°C.

The name comes from Grettir the Strong, the saga outlaw who is said to have swum from Drangey to the shore and warmed up in a spring here. Entry is around 2,000 ISK per person, paid by card at the small café, and there is a campsite with showers and a kitchen from April to mid-October. Drangey boat tours leave from Sauðárkrókur in summer, and the island makes a striking backdrop.

The honest downside: the road is narrow gravel and exposed to the weather, sources disagree on whether showers are open outside summer, and the pools can feel cramped when a group arrives.