Owned and operated by Associated British Ports, the tidal basin has the deepest berthing facilities in the Severn estuary and is one of only a few harbours in the UK capable of handling Capesize vessels of up to 170,000 tonnes deadweight (DWT),[2] mostly for the import of iron ore and coal for use by nearby Port Talbot Steelworks.

Aberafan had developed as a natural harbour from the 17th century at the mouth of the River Afan, acting as a point of transport for coal and sheep to South Wales, Bristol, and the West Country.

From 1750 onwards, tramlines connected the harbour to local coal mines, and the establishment of copper smelting and ironworks towards the end of the 18th century quickly developed volumes of trade.

Local Member of the UK Parliament, Christopher Rice Mansel Talbot of Margam Castle, recognised that improved transportation could stimulate industrial growth.

Completed in 1970, it was the first dry-bulk cargo terminal in the UK capable of accepting ships in excess of 100,000 tonnes deadweight (DWT).

Further dredging in 1996 deepened the harbour by 2.6 metres, increasing the maximum size of vessel that can be accommodated today to 180,000 tonnes deadweight (DWT).

In 1998, after being closed to shipping since 1959, the old floating docks were re-opened to handle coastwise cargoes of ground and granulated blast-furnace slag for Civil & Marine's new cement works at Rio Tinto Wharf.