The Zanzibar Channel is a

strait A strait is a water body connecting two seas or water basins. The surface water is, for the most part, at the same elevation on both sides and flows through the strait in both directions, even though the topography generally constricts the ...

in south-eastern Africa, separating the island of

Unguja Unguja (also referred to as "Zanzibar Island" or simply "Zanzibar", in – as mentioned in The ''Periplus of the Erythraean Sea'') is the largest and most populated island of the Zanzibar archipelago, in Tanzania. History Geography Unguja is ...

(also known as Zanzibar) from mainland

Tanzania Tanzania, officially the United Republic of Tanzania, is a country in East Africa within the African Great Lakes region. It is bordered by Uganda to the northwest; Kenya to the northeast; the Indian Ocean to the east; Mozambique and Malawi to t ...

. The channel is 120 km long and 29–37 km wide, with depth varying from a few dozen metres (in the centre) to a few hundred metres to the north and to the south. The channel is entirely located in Tanzanian

territorial waters Territorial waters are informally an area of water where a sovereign state has jurisdiction, including internal waters, the territorial sea, the contiguous zone, the exclusive economic zone, and potentially the extended continental shelf ( ...

. Sediment Distribution and Transport in the Zanzibar Channel
/ref> In ancient times the overall depth of the channel has been considerably smaller (about 120 m less during the last

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and g ...

). The southern entrance to the Channel is indicated by a

lighthouse A lighthouse is a tower, building, or other type of physical structure designed to emit light from a system of lamps and lens (optics), lenses and to serve as a beacon for navigational aid for maritime pilots at sea or on inland waterways. Ligh ...

located on the mainland coast on the Ras Kanzi

promontory A promontory is a raised mass of land that projects into a lowland or a body of water (in which case it is a peninsula). Most promontories either are formed from a hard ridge of rock that has resisted the erosive forces that have removed the s ...

, 22 km south of

Dar es Salaam Dar es Salaam (, ; from ) is the largest city and financial hub of Tanzania. It is also the capital of the Dar es Salaam Region. With a population of over 7 million people, Dar es Salaam is the largest city in East Africa by population and the ...

Swimming

In 2015, the 29 km solo swim across the Zanzibar Channel starting at the Pungume Sandbank was completed in 9 hrs 1 minute by Jean Craven (SA), Robert Dunford (Kenya), Megan Harrington Johnson (SA), Samantha Whelpton (SA) and Emil Berning (SA)

References

Straits of Africa Straits of the Indian Ocean Geography of Tanzania Zanzibar Archipelago {{zanzibar-geo-stub