It covers an Area of 61,000 ha. The city of Dar es Salaam sits on a natural harbour backed by low hills. The Important Bird Area runs from the open bay of RasKiramoni in the north, up to and including Ndege Beach, to RasNdege, east of Mbwamaji village a total length of 40 km. The inland limit of the site is the high-tide mark, but this is extended in places to include mangroves and salt-workings. To the seaward side the site extends out to the 12 km international limit.

This allows inclusion of important feeding grounds for several seabirds which rarely venture inshore of the coral reef. Within the Important Bird Area are tidal mudflats, river inlets, saltpans, extensive mangroves, coastal thicket and several offshore islands which create a remarkably diverse coastal environment. With a tidal range of nearly four metres, up to 25 km² of exposed sand and mud can be available to birds at low tide.

A total of 457 bird species have been recorded from the site. The area is of major importance to migratory waders from northern Eurasia, supporting about 30,000 birds. This includes large numbers of Calidrisferruginea, Calidrisminuta and Pluvialissquatarola. Large flocks of some species, notably Tringanebularia and Charadriusmongolus, are a feature of the return migration to northern latitudes during March and April. The only local populations of Egrettaardesiaca feeds at Msasani Bay and probably breed in the freshwater swamps adjacent to the now defunct Msasani saltpans, an area of low-lying land unsuitable for building which is, nonetheless, rapidly being urbanized.

The offshore island of Mbudya provides safe nestsites for Plataleaalba, Egrettadimorpha and Threskiornisaethiopicus. Sterna dougallii bred on islets off the harbour entrance. There are populations of an Acrocephalus warbler on the offshore islands that may not be Acrocephalusscirpaceus. Records of Acrocephalusgriseldis suggest that several winter in coastal scrub near Mbezi Beach and Jangwani Beach wherever there is thick cover and a source of fresh water.