The Belmont Anti-Tank Ditch was an anti tank ditch constructed in 1942 as part of the southern perimeter defensive system of the Port of Newcastle, New South Wales, Australia, as part of Fortress Newcastle during World War II. The anti-tank ditch was located 12 kilometres south of Newcastle, south of the town of Belmont. At the time it was anticipated that the Imperial Japanese Army may attempt a beach landing between Belmont and Swansea Channel along Nine Mile Beach. Barbed wire fencing and machine gun emplacements were constructed along the entire length of Nine Mile Beach.