Bertraghboy Bay is a scenic and productive saltwater bay on the Atlantic coast of Connemara in County Galway, Ireland. It serves as the tidal estuary for the renowned Ballynahinch River system, which drains a vast 68-square-mile catchment of interconnected loughs and rivers. The bay itself provides sheltered waters and is the gateway for migratory salmon and sea trout entering the freshwater system upstream. The surrounding area is characterized by rugged Connemara landscapes, with the village of Roundstone situated on its shores. The bay is also an active marine research site focused on sustainable aquaculture.