Greymouth is a standard Vogel Cass 2 or Gable station. Framed and clad in timber, it is narrow and long with the town elevation marking the edge of Mackay Street. There is a lean-to verandah supported by chamfered timber columns with diagonal braces, wrought iron brackets and decorative insets. This verandah is extended to either end of the station building by a freestanding shelter. The roof of the building is gabled. All rooms or offices are entered from the platform: the ticket office also has an entrance from Mackay Street. Most rooms are lit by sash windows with fanlights.
The first station in Greymouth was erected in 1876 to serve the first railway line on the West Coast, from Greymouth to Brunner coal mine. This structure, although extended, was eventually too small and was replaced in 1897 by the present building. As early as 1905 the new building was being criticised as inadequate. This criticism continued for many years, prompted by what was perceived as the lack of size and poor condition of the building. The station yard was significantly rearranged in 1925-26 when nearby private land and buildings were taken to improve accommodation. The clamour for a new station did not cease, however, and prompted District Traffic Manager J. Chapman to attribute the problem to the arrival of the twice-daily Christchurch train, "the event in Greymouth", and the consequent deluge of people onto the platform. Meanwhile the building continued to be enlarged. The parcels office was extended in 1920 and a porters' room added in 1926. The platform (in 1934) and the verandah (in 1936) were extended and in 1947a partition was erected between the waiting room and ticket lobby. The building was augmented by Railways’ district office, in a nearby building. Both freight and passenger business declined in the 1970s as a result of road competition and the drop in coal and timber output. It was refurbished extensively by Tranz Rail in 1998, and small outbuildings removed from the platform.