The original South Quay station opened in 1987 in Millwall, and was a standard DLR phase 1 elevated station. It was later extended to permit the use of 2 car trains. The station was constrained by sharp curves at both ends and could not be further extended on its original site. The DLR planned to operate 3 car trains on this line so the station was relocated to a new site over Millwall Dock. The new site is some distance to the east, so the relocated station is partly in Cubitt Town.