The Porcupine Seabight is a deep-water basin in the Porcupine Bank in the northeastern Atlantic Ocean. It lies southwest of Ireland and is approximately 180 nautical miles (north-south axis) by 100 nautical miles (east-west axis). The feature is shaped roughly like an amphitheatre with the deepest point (approximately 3000 metres) lying to the southwest. Beyond the deepest point and southwest of the Porcupine Bank lies the Porcupine Abyssal Plain.
The basin lent its name to Operation Seabight, an Irish drug bust in November 2008.[1]