The Site is a large and very sheltered estuarine system with a narrow outlet to the sea and extensive mud and sand flats, saltmarshes and sand dunes. It contains natural examples of marine habitats and natural wetland types which are representative of the Atlantic biogeographic region. The saltmarshes feature exceptional species diversity. The Site’s Mediterranean and thermo-Atlantic halophilous (salt-tolerant) scrub (of the class Sarcocornetea fruticosi) is the rarest in Ireland of the saltmarsh habitats in Annex I of the European Union’s Habitats Directive. Bannow Bay supports a notable diversity of wintering waterbirds, for which it is one of the most important Sites in the south-east of the country. More than 1% of the global population of light-bellied brent goose, and notable populations of shelduck (Tadorna tadorna), little egret (Egretta garzetta), golden plover (Pluvialis apricaria), lapwing (Vanellus vanellus), black-tailed godwit, bar-tailed godwit and curlew are found. Bannow Bay is used for recreational, scientific and educational purposes. The invasive common cordgrass (Spartina anglica) is a threat to the intertidal mudflats and Salicornia flats, and the removal of sediment and beach material, erosion, discharges and off-road driving pose significant threats to the ecological character of the Site.