South of the Royal Albert Dock was the King George V Dock. Completed in 1921, the new dock was well over a kilometre long (4000 feet). It averaged about 200 metres (650 feet) wide and had some 5 kilometres (3 miles) of quays. Its entrance lock from the river, the largest in the Port of London, was about 250 metres (800 feet) long and 30 metres (100 feet) wide.
Through it passed the ships of the Blue Star Line, British India Steam Navigation Company, Shaw Savill, Albion Line and P&O group. The Royal group of docks together formed the largest area of enclosed water in the world. The maximum loaded draught of vessels using the dock was 10 metres (nearly 33 feet). Ships of up to 30,000 tons could be accommodated in the King George V Dock. The largest to use it was the 35,000-ton RMS Mauretania in 1939.