Ol Doinyo Lengai is an active volcano in the Rift Valley, rising alone above dry plains 16 kilometres south of Lake Natron. The Maasai know it as the Mountain of God, and the climb to its crater rim makes for a very demanding day on foot. It suits fit, determined walkers who want something raw and steep after the national parks, and it appeals to climbers who come down from Kilimanjaro still hungry for another summit.

A volcano like no other

Lengai is the only volcano known to erupt natrocarbonatite, the coldest and most fluid lava known. It pours out black and turns white as it weathers, which is why the upper slopes can look dusted with snow from a distance. The summit stands at roughly 2,960 metres, although the height shifts as the cone grows. The last big explosive eruption came in 2007 and 2008, and there has been low-level activity inside the crater since around 2017. Conditions at the top change, so your guide decides on the day how close it is sensible to go.

Climbing Ol Doinyo Lengai

To avoid the heat, the climb is done at night. You set off at about midnight and reach the rim close to sunrise, after five to six hours of climbing. Coming down takes another three to four hours and, for most people, is the hardest part.

Steep and loose: there is little in the way of a path, just ash and rock at a punishing angle
Local guide: you climb with an experienced guide from the Engaresero area
Kit that helps: sturdy boots, gaiters, a head torch, plenty of water and poles for the descent

When to go

June to October and December to February are the drier, safer windows. Avoid April and May, when rain makes the ash slopes slick and dangerous. Nights at the foot of the mountain are warm, but the rim can be windy and cool at dawn. Our Tanzania weather guide covers the seasons in more detail.

Getting there

From Arusha the drive takes five to seven hours via Mto wa Mbu, and the final 120 kilometres or so are on gravel through dry Maasai country. Most people reach Engaresero in the afternoon, eat early and sleep a few hours before setting off.

How it fits your trip

Lengai works better as part of a few days around Lake Natron than as a quick detour. Lesser flamingos breed on the soda lake to the north, a walk up the Ngare Sero gorge leads to a waterfall, and the old stone ruins at Engaruka lie on the road in. If you are arriving straight from a Kilimanjaro climb, take at least one rest day first. This is a serious extra ascent on very different ground, not a gentle walk to round off the trip.

Where to stay

Places to stay near Engaresero range from simple campsites to tented lodges with views of the volcano. Facilities are plainer than on the main safari circuit, which is part of the area's character. Send us your dates and we will plan the climb around the rest of your journey.