At the time of writing Hekla was closed to hikers because of a worries over potential eruption. Usually, the return hike to the top takes around eight hours, involving rough gravel terrain with snow higher up; you need to contact Ferðafélag Íslands, the Icelandic Hiking Association (w fi.is) for advice about current routes and conditions. Alternatively, Arctic Adventures (w adventures.is) lead day-hikes to the summit.