Trekking Mount Karthala Volcano and the Iconi Cliffs

Rising directly behind Moroni to an altitude of 2,361 metres (7,746 feet), Mount Karthala forms the entire southern two-thirds of Grande Comore. It is one of the largest active shield volcanoes on earth, crowned by a vast, lunar summit caldera measuring roughly three by four kilometres across, and has erupted more than twenty times since the 19th century (most recently in 2005 and 2007).

Day hikes vs two-day summit caldera treks from Mvouni

Because Mount Karthala rises all the way from sea level to 2,361 metres over a short horizontal distance, climbing to the crater rim and back involves roughly 1,900 metres of vertical ascent and descent from the highland trailhead village of Mvouni (at 400 metres altitude, fifteen minutes' drive above Moroni). Never attempt the trail without a certified local mountain guide arranged through the CNDRS museum, your hotel or a registered trekking association; paths split through dense cloud forest, mobile signal vanishes, and mountain mist rolls in rapidly after midday.

Endemic cloud-forest birds and the Choungou crater

• The Two-Day Overnight Summit Trek (recommended): set out from Mvouni before dawn to climb through four distinct ecological zones: lower ylang-ylang, banana and clove plantations; mid-altitude tropical evergreen cloud forest draped in orchids, giant tree ferns and mosses (home to four bird species found nowhere else on earth, including the Karthala scops owl and Karthala white-eye); and upper sub-alpine heath of giant Philippia heather trees. You reach the Convalescence plateau and the caldera rim by early afternoon, peer down into the smoking Choungou Chagnouméni inner pit crater, camp overnight in tents on the rim (bring a warm sleeping bag and fleece, see what to wear), and watch sunrise over the Indian Ocean before descending the next morning.
• Strenuous Single-Day Ascent or Cloud-Forest Half-Day Walk: strong hikers departing before dawn can reach the rim and return in a single ten-to-twelve-hour day, while travellers preferring a gentler outing can take a four-hour guided morning walk through the lower plantations and bird-rich cloud forest above Mvouni or Boboni.

The historic cliff fortress and palace ruins of Iconi

On the coast just seven kilometres south of Moroni at the foot of Mount Karthala lies Iconi, the former capital of the Bambao Sultanate. Climb the steep volcanic cinder cone of Goulaivoini cliff rising straight out of the surf, where in the early 19th century women of the town famously leaped into the sea rather than be captured by raiding Sakalava and Betsimisaraka pirates from Madagascar. Down in the town below stand the coral-stone ruins of the 19th-century Kaviridjeo Palace and an ancient stepped mosque. Cool off afterwards at the beaches in our coastal overview.