Also referred to as Mahameru ("Great Mountain"), Mt. Semeru is a stratovolcano in the Bromo-Tengger-Semeru National Park, in the province of East Java. Semeru is one of Indonesia's most active volcanoes. What stands out most about this mountain is the fact that it erupts periodically (and very reliably so). Every 20 minutes or so, the volcano belches out a huge cloud of steam and smoke, sometimes interspersed with ash and stones. The scenery on the way is beautiful (the erupting volcano, the mountain savannah, the lake), and the views from the top are spectacular. You see the vast Sandsea caldera with other volcanoes, among them Bromo and Batok, and the sea. Semeru is a must for all mountaineers, hikers and nature lovers who happen to be in Indonesia. If you are flying from Denpasar to Surabaya, you can see Semeru, and you may see a horizontal chain of clouds stretching away from the peak. These clouds all have the same distance to each other due to the volcano's periodic activity. Many people climb this mountain, tourists and Indonesians alike.
HOW TO REACH SEMERU
Most visitors will arrive via Indonesia's major gateway airports Denpasar (Bali) or Jakarta. The closest domestic airport is inSurabaya, about 3 hours' drive away. Now there are flights from Jakarta to Malang.
The starting point of the hike is the village of Ranupane. You can get there either via Malang and Tumpang or via Pasuruan/Probolinggo, Sukapura, Ngadisari, and Cemoro Lawang (see Mount Bromo for details on these).
You can take a microbus from Malang to Tumpang, and then a 4WD vehicle from Tumpang to Ranupane. But the latter of the above-mentioned routes is the more interesting because it leads across the 9-km-wide Sand Sea caldera and passes Bromo, a post-caldera cinder cone. A dirt road leads across the flat bottom of the caldera, up to Jemplang on its southern rim, and on to Ranupane. You have take a 4WD vehicle (unless you prefer to walk).