Overview
The caldera holds Segara Anak, a crescent lake with hot springs on its shore, and Barujari, the cone that has grown inside it and erupted several times this century. Routes start at Sembalun, which is longer and gentler, or Senaru, which is steeper and shaded; both need a permit booked online and both are closed in the wet season, roughly January to March. Porters carry the loads on this mountain, often barefoot and heavily laden, and the choice of operator determines how they are treated.
Highlights
The rim at Sembalun is the realistic objective for most people; the summit push starts around two in the morning on volcanic scree and turns back many who attempt it. Book through an operator that publishes its porter weight limits and pay rates. Nights on the rim are near freezing, which the daytime heat at the trailhead gives no hint of.