The Llanelly Railway & Dock Company opened the New Dock in 1833. It was the first dock along this stretch of coast to have gates (so was known as a wet dock). The Great Western Railway took over the dock in 1889 and over time it became known as the Great Western Dock. The New Dock gave its name to that part of the town.
It began to lose tonnage after WWI and although there was a boost in the second world war it declined along with the port. However, it remained in railway ownership following nationalisation of the railways in 1948 and was used in a small way until the 1960s.