In total, the archipelago covers a land area of 8.5 km2 (3.3 sq mi),[1] and has an average elevation of 11 m (36 ft).

Tanzania's geological history is very similar to that of Western Australia's northwest shelf.

It has rifting from the late Jurassic, then sags in the Cretaceous and Tertiary continental shelves.

The largest natural gas deposits in Tanzania are located in the Songosongo archipelago.

[3] The Islands have been found to contain 20 million tonnes worth of natural gas within the archipelago.