Mount Semeru

Semeru reaches 3,676 metres, the highest point in Java, and it is in near-continuous eruption - the Jonggring Saloko crater has been throwing an ash and gas plume at intervals of roughly fifteen to twenty minutes for decades, visible from far off and audible from the upper mountain. The climb goes from Ranu Pani past two crater lakes, Ranu Kumbolo and Ranu Regulo, over the Tanjakan Cinta rise and the Oro-oro Ombo savanna to Kalimati camp, and then up a punishing slope of loose volcanic sand to the rim. Official access stops at Kalimati; the summit push is not sanctioned and has killed a number of people, most famously the activist Soe Hok Gie in 1969, from gas and from falls. Pyroclastic flows in 2021 killed dozens in villages below.

What you actually see

• Java's highest point - 3,676 metres, erupting every fifteen to twenty minutes.
• Ranu Kumbolo - the crater lake camp on the approach, and the savanna beyond.
• A loose sand summit slope - the punishing final climb, where progress slips backwards.
• An actively dangerous volcano - deadly gas at the rim and flows that killed in 2021.

When to go

May to September; permits booked well ahead. Four days.

Honest expectations

Permits, quotas, medical certificates and guides are all required and enforced. Official access ends at Kalimati - the summit is not sanctioned and people die there. The mountain closes on alerts.

Nearby

Bromo and the Tengger caldera are north; Malang is west.