The Site covers most of an island within the wider coastal and estuarine waters of Dublin Bay. Salt marshes extend along the length of the landward shore, and a well-developed and dynamic dune system along the seaward shore, where annual vegetation of drift lines is found in places. The island shelters two intertidal lagoons divided by a causeway. The dunes and salt marshes support characteristic plant communities and a number of rare plants which are legally protected. The intertidal habitats feature a rich macrofauna, small areas of eel grass and, in the summer months, green algal mats. The wider estuarine complex provides feeding and roosting habitat for more than 1% of the global population of more than 20 wintering birds, including black-tailed godwit (Limosa limosa) and light-bellied brent goose (Branta bernicla hrota). The Site also supports notable invertebrates. It is a very popular recreational area and important for educational and research purposes: nature conservation is a main land use within the Site. Much of the land surface of the island outside the Site is taken up by two golf courses. Due to its proximity to the Dublin urban area, the Site is impacted by urban wastewater, extensive tourism and roads.