Mount Rinjani

Mount Rinjani is an active volcano in northern Lombok and, at 3,726 metres, the high point of the island and one of the highest peaks in Indonesia. It sits inside Gunung Rinjani National Park, which also forms part of a UNESCO Global Geopark. The mountain's defining feature is its caldera, a vast collapsed crater holding the crescent lake Segara Anak, with the younger cone of Gunung Barujari rising out of the water. Rinjani is genuinely active and has erupted within living memory, so the park's status can change at short notice.

Every climb needs a park permit booked through the national park's online system, and you must trek with a registered guide. Entry is capped by a daily quota per route, so places on popular dates go well before you arrive, and turning up at the gate hoping to join something is not a plan. A park entry fee applies, and it has been revised more than once, so confirm the current amount and the accepted payment method through official park channels rather than an older write-up. Trails also close during the wet season, with the dates announced season by season, so check the park's current status before you book flights around a climb.

Two villages carry almost all Rinjani traffic, Sembalun on the east side and Senaru in the north, and most itineraries run two or three days between them. Sembalun starts across open grassland and gives the shorter, more direct approach to the crater rim and the summit. Senaru climbs through forest and is the wetter, shadier side. A common shape is up from Sembalun, a night on the rim, a pre-dawn summit attempt, then down past the lake and out at Senaru. The Torean route on the north side is a rougher alternative used mainly to reach the lake.

The summit is the hardest part of the trek by a wide margin: a pre-dawn start on loose volcanic scree where you slide back with every step. Groups commonly leave the rim camp at around 2am to reach the top for sunrise, and the climb often takes three to four hours up for far less coming down. On the other side of the rim, Segara Anak lies in the caldera with hot springs a short walk from the shore, and plenty of trekkers rate the lake above the summit. Reaching it means a steep descent and an equally steep climb back out.

Rinjani is a demanding multi-day trek, and what turns people back is usually cold and loose ground rather than distance. Nights on the rim are close to freezing and windy, the trail is steep and slippery in both directions, and the daytime sun on the exposed grassland is punishing. Bring broken-in boots with grip, a warm layer and a windproof one, a head torch, sun protection and more water than feels necessary. Porters carry the group camping equipment on most trips. If you have knee trouble, the descent is what will find it.

Expect no usable signal for most of the trek, including down in the caldera, and no eSIM changes that. As of July 2026, Senaru and Sembalun villages have workable 4G, and Goodbars runs on Telkomsel, which reaches further across Lombok than any other Indonesian network. On the mountain itself, coverage runs from unreliable to absent: a bar may appear on an exposed ridge and vanish a minute later, and at the lake there is nothing to depend on. Treat the trek as offline. Download maps, send what matters and leave your route with someone while you are still in the village, and carry a power bank, because cold drains a phone battery fast.