The Ijen Plateau is a large upland area southeast of Bondowoso, which includes the peaks and foothills of Gunung Ijen, Gunung Raung (3332m), Gunung Suket (2950m) and Gunung Merapi (2800m), plus several smaller peaks. The entire area is rural, coffee plantations and vegetable gardens blending into the forested uplands, with a few widely dispersed villages. The highlight is the dramatic lake, Kawah Ijen , in the crater of the dormant volcano from which dozens of miners dig sulphur by hand.

The usual access to the crater lake is a three-kilometre (90min) hike from PAL TUDING , where there's a campsite, dorm (under $5; bring a sleeping bag), caf?, and national park office (Rp1000 park entrance fee). From Pal Tuding, the path heads steeply uphill through the forest and is easy to follow. After 45 minutes it passes a building, and the climb steepens. Just above here the path splits; the right fork, the best route, leads to the crater rim and the left fork to the dam at the end of the lake. After a while you find yourself 200m above the lake in a dramatic, austere landscape of almost bare rock sloping down into the crater. You can walk along the top of the crater, or descend to the edge of the lake along the narrow path that the sulphur miners use - allow 30 to 45 minutes to get down, and twice that to get back up. The sulphur miners come up to Kawah Ijen daily; they set off from the Banyuwangi area before dawn, walk up to the lake from Licin, hack out a full load of sulphur (50-70kg) by hand, which they bring up to the crater rim and back down to Licin where they receive around Rp125 per kilo. It's dangerous work, and sudden eruptions and sulphur fumes have been known to kill miners.

From Bondowoso there are four buses daily to SEMPOL , the main village on the plateau (66km; 3hr); from Sempol you have to hitch or use an ojek (Rp10,000 one-way) to get to Pal Tuding. The most convenient place to stay is at the national park office area in Pal Tuding, but it's also possible to stay near Sempol, 1km from the main road in the hamlet of Kalisat , at the guesthouses, Jampit II and III (no phone; $5-10), which are signposted "Penginapan Kaliasat" from the centre of Sempol. Staff here can arrange excursions to Kawah Ijen, local guides, transport and inexpensive food.