Kilcoole Marsh is a significant coastal wetland and estuarine system on the east coast of County Wicklow, Ireland, running alongside Kilcoole Beach. It is a designated Site of Special Protection (SPA) due to its high ecological value, particularly for breeding seabirds. The marsh is influenced by tidal action from the Irish Sea, with "The Breaches" acting as a dynamic connection point that can close off, effectively impounding the marshes at times. This creates a mosaic of saltmarsh, intertidal channels, and sheltered coastal waters adjacent to a long, sandy beach, offering a unique inshore fishing environment within an hour's drive south of Dublin.