The Hub was located directly below Roald Dahl Plass in Cardiff Bay, built in and around the remains of a Victorian water pumping station.

It was accessible by a lift at the water tower which benefited from the effects of a perception filter, making whoever used it invisible. The main entrance, however, was disguised as a Tourist Information Centre on Mermaid Quay. There was also an entrance hidden in the basement of the Bute Place car park which was used for the Torchwood SUV.

The main hall of the Hub included workstations, the Rift Manipulator and entrances to other rooms. The lowest level of the central area was several inches deep in water and hosted a colony of mosquitoes in the summer. The water rose and fell with the tide, sometimes trapping fish. It had a valve to prevent flooding.

Upstairs was an office used by Jack Harkness, where he kept his personal belongings. Rooms located off of the main room included the autopsy room, the interrogation room and the boardroom. Other rooms included the cryo-chamber room, the holding cells and the firing range.

The Hub was destroyed during the 456 incident.