This estuarine system fed by two small rivers, the Mayne and the Sluice, is separated from the sea by a major sand dune peninsula. It is part of the Dublin Bay wetlands complex. In the inner estuary there are extensive beds of common cord-grass, while seawards vast mudflats are exposed at low tide. These characteristic habitats provide good quality feeding areas and roost sites for a wide range of birds such as the regionally threatened pale-bellied brent goose (Branta bernicla hrota), which winters there, and the nationally threatened Eurasian oystercatcher (Haematopus ostralegus). The area surrounding Baldoyle Bay is densely populated, and most of the dunes sheltering the Site are now used as a golf course. The main threats to the Site include the disturbance to wildfowl by the high number of visitors, and the dumping of spoil onto the foreshore. Besides recreation and research, the Site is important for erosion protection and flood control.