Banaba is the only raise limestone phosphate island in Kiribati. It rises 81 meters at its highest point above sea level and has land area of 6.9 sq.km. It is surrounded by a fringing reef and has no lagoon. After the mining, the land was cut down by 20 to 30 meters. Banaba has a total population of 268. (Population Censes, 2015)

The island, as described by the first European to visit Banaba in the early 19th century, was rich in plant and bird life but there were also times that the island went through a severe drought and affected all the crops, which the Banaban people depend on for survival. Water on the island is scarce as there is no well, only stored rain water, when there is rain. During a drought, the islanders fetch water from inside a cave which can only be consumed within the day it was brought up to the surface. The water fetched from the cave is undrinkable if it is left undrunk for more than a day.

With the discovery of the phosphate on the island and the subsequent mining of it from the early 20th century, rock pinnacles are now observably the main physical feature of the island along with the derelict phosphate mining infrastructure and the abandoned homes of those who once lived and worked on Banaba.

After the WWII, some of the islanders were relocated to a piece of land in Fiji which was bought from the money earned from mining of Banaban phosphate, called Rabi. Banaba Island was also a Japanese base during World War II.