Work started in 1817, under the direction of the engineer William Kirkhouse, and the canal was completed by autumn 1818, running from near the east pier on the River Tawe at Swansea to the River Neath at Red Jacket. The canal was built to a grander scale than originally intended, and could be navigated by barges of . The main line was long, and the branch to Glan-y-wern was also reopened, for it supplied regular cargoes of coal. Other goods carried included timber, bark, fire-bricks and sand, but the volume of goods carried was not enough to make a profit. He negotiated with the Neath Canal, who gave him permission to build a lock into the river from their canal, either at Giant's Grave or Court Sart pill, but working canal boats across a tidal river would not have been ideal, and he did not build the lock.