The water is such an intense green that it seems unreal, almost painted by someone with too much imagination. Dziani Dzaha suddenly opens up before the eyes after a short walk in the lush greenery of Petite-Terre, the small twin island of Mayotte that hosts the administrative capital Dzaoudzi. This is not an optical illusion or a photographic filter: that bright emerald color is the direct result of the unique chemistry of these waters, rich in sulfur compounds and algae that thrive in a volcanic environment unique in the Indian Ocean.
Mayotte is a French overseas territory located in the Comoros archipelago, between Mozambique and Madagascar. Dziani Dzaha is one of its lesser-known treasures, often overlooked by travelers who focus on the coral lagoon — one of the largest in the world — without ever venturing inland to Petite-Terre. However, those who take the time to climb to the edge of the crater find something hard to forget.
A volcanic crater in the middle of the ocean
The lake occupies the caldera of an ancient extinct volcano, and its almost perfectly circular shape is clearly visible from above. The dimensions are not huge — the lake has a diameter of about 160 meters — but the depth and concentration of volcanic minerals give the water that characteristic emerald green color. The waters are sulfurous and slightly acidic, which makes them unsuitable for bathing, but extraordinarily photogenic and biologically interesting.
The particular chemical composition of the lake has over time selected a fauna and flora adapted to extreme conditions. Some species of algae and microorganisms manage to survive in this environment that would be hostile to most aquatic organisms. It is precisely this biological specialization that makes Dziani Dzaha a site of scientific interest as well as scenic beauty.
The flamingos and the fauna of the crater rim
One of the most surprising sights of Dziani Dzaha is the presence of flamingos on the shores of the lake. These birds with pink plumage frequent the waters of the crater, and seeing them reflected on that intense green surface is an image that stays etched in memory. Their presence is linked to the availability of algae and small filterable organisms in the sulfurous waters, a habitat that few other birds would be willing to tolerate.
In addition to the flamingos, the path leading to the lake crosses dense vegetation where it is possible to observe typical island birds and, with a bit of luck, lemurs moving among the trees. Petite-Terre indeed hosts a small population of ring-tailed lemurs, introduced to the island in recent times, which have adapted to the local vegetation.
How to get there and when to visit
Dziani Dzaha is located on Petite-Terre, reachable from Mamoudzou — the main town of Grande-Terre — via the ferry that connects the two islands, with frequent crossings during the day. From Dzaoudzi, the path leading to the lake is walkable and takes about 20-30 minutes to walk on a route that is not particularly challenging, although it has some uphill sections. It is recommended to wear closed shoes with good grip, especially in the wet seasons when the ground can become slippery.
The best time to visit the lake is in the early morning, when the slanting light enhances the color of the water and the temperatures are still bearable. Mayotte has a tropical climate with a dry season (from May to November) and a rainy season (from December to April). The dry season is generally preferable for hiking, with drier trails and better visibility. It is advisable to bring enough water, sunscreen, and insect repellent.
A place still outside the mass circuits
Dziani Dzaha remains one of the least visited places in Mayotte, despite its relative accessibility. Foreign visitors who reach Mayotte are still few compared to other destinations in the Indian Ocean, and of these, a minority venture to the edge of the crater. This means that it is possible to enjoy the view in almost absolute quiet, with only the sound of birds and the wind through the vegetation.
There are no tourist facilities at the edge of the lake — no bar, no information point — and this helps to maintain the wild character of the place. Bringing everything you need from Dzaoudzi is essential. Respecting the site by not leaving waste is crucial to preserving an ecosystem that is already fragile by nature. Those seeking spectacular volcanic landscapes away from the crowds will find in this emerald lake one of the most powerful images that the Indian Ocean has to offer.
