When to visit Lac Dziani?

Count 1h30 to 2 hours for the complete tour of the panoramic trail (4 km, modest 100 m elevation). Marked trail but sandy and stony in places, without major technical difficulty but requiring suitable shoes. With photo stops and contemplation at the top, count 2-3 hours on site. Leave early in the morning (before 9am) or in late afternoon (after 4pm) to avoid the heat.

No, swimming is strictly prohibited in Lac Dziani. Two reasons. Ecological: the water is saline (salinity higher than the sea) and alkaline (pH 9), unsuited to human skin and fragile for the ecosystem (cyanobacteria giving the emerald colour). Cultural: the lake is sacred to the Mahorans, and several traditional ceremonies take place there. Absolute respect of the prohibition. For swimming, go to Moya beach 3 km south.

Lac Dziani is in northern Petite-Terre, 2 km north of Marcel Henry airport. Several options. On foot: 20-25 minutes from the airport or 30 min from Dzaoudzi. Taxi: 5 min from the airport (€4-6) or 8 min from Dzaoudzi (€5-8). Collective taxi: €2-3 from the airport. By car: free parking at the foot of the trail.

Early morning (5:30-9am) or late afternoon (4-6pm). Early morning: coolness, soft orange light, maximum visibility, possible observation of brown lemurs in the trees. Late afternoon: golden light, more bearable temperatures, spectacular exit of giant fruit bats at dusk. Avoid the 10am-3pm slot: violent sun, little shade, stifling heat. In rainy season (November-April), the trail is muddy and slippery.

The intense emerald-green colour is due to cyanobacteria (photosynthetic bacteria) that develop in its extreme environment: saline water (salinity higher than the ocean), alkaline water (pH 9), sulphurous water and low depth (4 metres). These conditions favour the proliferation of green filamentous cyanobacteria that colour the water. These bacteria are the oldest forms of life on Earth — ancestors of plants — and produced our atmosphere's oxygen 2.5 billion years ago. NASA has conducted studies on Lac Dziani as an analogue of extraterrestrial environments. It is a site of global scientific interest.

The panoramic trail offers exceptional 360° views. South: Pamandzi and the airport, the whole of Petite-Terre. West: Grande-Terre and Mamoudzou (in clear weather). North and east: the open Indian Ocean. At the foot of the trail: the lagoon with turquoise waters, white sand beaches below. Fauna: brown lemurs in trees (morning), giant fruit bats (dusk), birds. Notable trees on the trail: dwarf baobabs, tamarinds, jackfruits, mangoes.