Lake Tanganyika runs along the lagoon of Bujumbura city and the neighboring provinces:  Bujumbura, Rumonge and Makamba, and extends to three other riparian countries further in the south: The United Republic of Tanzania, the Democratic Republic of Congo and Zambia. 12 million years old, Lake Tanganyika is the oldest of the African Rift Valley. It is the 2nd deepest lake in the world after Lake Baikal of Russia. 800 km long and 50 km wide on average, it drains a basin of about 220 000 km² and is the largest freshwater reservoir in Africa. The lake contains a rich fauna, including 250 species of fish, more than 145 species of non-cichlids and invertebrates, including 60 species of gastropods and many more.

Lake Tanganyika has long been an important channel of communication and trade. The lake offers sandy beaches, possibilities for water sports, recreational angling and underwater diving. There are numerous resorts, restaurants, pubs and hotels along the lakeshore, for the pleasure of tourists and locals.