About the Landmannalaugar tour from Reykjavík
Landmannalaugar is in the Fjallabak Nature Reserve in the Highlands, and it only opens when the mountain roads do, usually from June. The hills here are rhyolite, so they come in shades of orange, pink, green and grey, cut by black obsidian lava. You cannot drive there in a normal car, which is why a 4x4 bus tour is the easy way in.
The day is long, about 13 hours, and much of it is driving on gravel and rough Highland roads. In return you get around four hours at Landmannalaugar. Your guide leads an optional hike of 1.5–2 hours on the loop through the Laugahraun lava field and Grænagil gorge, about 4.5 km on uneven, rocky ground. If you want more of a climb, you can hike up Bláhnúkur on your own instead, which takes about 2.5–3 hours.
After the walk you can bathe in the natural hot spring by the hut. The water is warmer where the hot stream flows in, and cooler further away. There is no restaurant in Landmannalaugar, only a small shop with snacks, so bring a packed lunch.
The weather in the Highlands can change fast, even in July. Bring a proper rain jacket, warm layers and good shoes, and expect wind, rain or sun on the same day.