This is one of the few opportunities in the world where you can run to a natural river thermal spring! Located on the ‘Golden Circle’ tour, the thermal river at Hveragerdi, known as the Reykjadalur, is a 3.5 km path through a mountain valley to a natural hot spring thermal river. From the parking lot, it is a steady climb, but not steep, along a wide and well-traveled path. It’s 3.5 km (2.2 miles) one-way from the parking lot to the thermal spring, where can refresh with a soak in the river’s perfect temperature.
If you’re with a partner, one option is to walk/hike to the river, and then run back to the parking lot. You can even continue from the parking lot into the town of Hveragerdi along a dedicated path (sign in parking lot, and keep following the red markers), for 3.2 km. There’s also a bathroom and cafe at the parking lot.