Hot spring bathing in South Iceland

Reykjadalur, the 'steam valley' above Hveragerði, is the most rewarding of Iceland's wild hot springs: a warm river running through a green geothermal valley, where you hike up past steaming vents and bubbling mud to a stretch of stream you can actually bathe in.

The magic is that the water gets hotter the further upstream you go, so you choose your perfect temperature simply by where you settle — cooler downstream, near-scalding at the top.

Soaking in a natural hot river, steam rising around you, mountains all around and not a tiled pool in sight, is a quintessential Icelandic pleasure, and doing it for free after earning it on foot beats any commercial spa.

Under a dusting of snow or the midnight sun, it's a simple, soul-restoring experience and one of the loveliest things to do in the south.

A hike of around 3 km each way up a geothermal valley, gaining a few hundred metres past steaming ground, hot springs and bubbling mud, to a warm river where you can bathe.

The walk is moderate — a real uphill but manageable for most reasonably fit people and families — and can be muddy, snowy or windy depending on season.

At the top, a boardwalk with basic changing screens lets you get into the river; you pick a spot to match your ideal warmth, hotter upstream. There are no other facilities, so you carry your swimwear, towel and warm clothes for after.

The water is natural and unregulated, so you test temperature as you go and keep clear of the scalding sources. It's a simple, delightful reward for the walk, in a steaming, otherworldly valley.

You can go year-round, though summer is easiest underfoot and winter is atmospheric but can be icy — bring traction if there's snow. Drive to the Reykjadalur trailhead above Hveragerði, about 45 minutes from Reykjavík, and hike roughly 3 km up to the bathing stretch of river.

Bring swimwear, a towel, warm clothes and shoes for after (you'll be walking back damp), and water and a snack. There's a boardwalk and basic changing screens but no other facilities and no fee.

Test the water before getting in — it's hotter upstream and genuinely scalding at the sources, so keep clear of those and keep an eye on children. Stay on the paths to protect the fragile geothermal ground. It gets busy, so early or late is quieter.

No guide needed — just walk up and soak.