At 3,428 metres Mount Slamet is the highest peak in Central Java and the second-highest volcano on the whole island after Semeru. Its broad symmetrical cone dominates the horizon for fifty miles in any direction and forms a wall between the Banyumas plains around Purwokerto to the south and the Tegal–Pekalongan coast to the north. The mountain is still active, with regular gas emissions and occasional VEI-2 eruptions, and is climbed less often than the volcanoes around Yogyakarta — which is part of its appeal.
The standard hiking route starts from Bambangan, on the northern flank around the village of Serang, and is a two-day climb with an overnight camp at Pos 7. It is a hard ascent — long, exposed above the treeline, and bitterly cold at the summit before dawn — and should only be attempted in the dry season (June to September) with a guide arranged through one of the Purwokerto trekking operators. From the rim you look down into a deep, steaming crater and across to the distant cones of Sundoro, Sumbing, and on a clear day Merapi. Always check the current volcanic alert status before booking a climb.