South Dock was a railway station on the Isle of Dogs in east London. It was between Millwall Junction and Millwall Docks on the Millwall Extension Railway (MER) branch of the London and Blackwall Railway (LBR) which opened to goods traffic on 18 December 1871 and to passenger services on 29 July 1872. The station was on the northern side of the South Dock of the West India Docks, near the eastern end. It had an island platform as it was the only passing loop on the branch. The station buildings were of timber with a slate roof. Platform was brick faced.