An inlet within Sullom Voe on the N coast of the Mainland of Shetland, Garths Voe is located 4½ miles (7 km) northeast of Brae. The settlement of Graven lies at its head, while a complex of buildings and piers associated with the Sullom Voe Harbour, including the port authority administrative headquarters, lie on Sella Ness on its western shore. The deep-water jetties associated with the oil terminal are located a mile (1.5 km) to the northwest.
During World War II Sunderland and Catalina flying boats were based in Garths Voe, protecting shipping in the North Atlantic from German U-boats. The station was known as RAF Sullom Voe. RAF Scatsta was built a mile (1.5 km) to the southwest as a fighter base to protect the flying boats and this has subsequently become Scatsta Airport.