Mount Tambora

Mount Tambora is a stratovolcano on the island of Sumbawa in West Nusa Tenggara, Indonesia, with a summit elevation of roughly 2,850 metres. It is world-famous for a massive eruption in 1815 that produced a large summit collapse and global climatic impacts.

Hiking to the caldera rim and exploring the rim and inner slopes are primary visitor activities; trails and base camps are used by organised trekking groups. The volcano’s 1815 eruption reduced the summit and left a prominent caldera that is the main geological attraction. Local guides and established routes are generally used because of the mountain’s remoteness and the length of the trek.

The modern volcano was dramatically altered by the 1815 eruption, one of the largest in human history, which destroyed villages and caused widespread loss of life at the time and climate anomalies in subsequent years. The summit collapsed to form a large caldera and the edifice has since partially recovered through later volcanic deposits.

Geographically Tambora rises on northern Sumbawa in the central Lesser Sunda Islands of Indonesia and is reached from regional ports and towns on Sumbawa’s north coast; the surrounding landscape is tropical and relatively sparsely populated.

• 1815 eruption: The 1815 eruption is classified as VEI 7 and is one of the largest volcanic events in recorded history, with global climatic effects in the following years.
• Elevation and trekking: Summit elevation approximately 2,850 metres, with routes that typically require multi-day trekking to reach the caldera rim.

What to See#

• Summit caldera: The large summit caldera formed by the catastrophic 1815 eruption, which is a major destination for trekkers who visit the mountain to view the crater rim and inner caldera landscape.

• Plan a Tambora trek during the local dry season (roughly May-October) when trails are most stable and summit views are likelier; monsoon months make routes muddy and unpredictable.
• Hire a local, experienced guide and start ascents very early (pre-dawn) to reach viewpoints before afternoon cloud build-up and to maximize daylight for exploring the caldera area.