With various exhibitions across Cardiff Bay including in the West Bute Dock Basin (NPRN 34288) and the Butetown Railway Station (NPRN 31744), the main exhibition space was constructed in 1975?77 to the design of H. M. R. Burgess & Partners. Modern in style, the building consisted of a simple rectangle with red-painted I-beams carrying a flat space-frame roof masked by a black fascia. The red-brick walls had glazing at the eaves level. Three large round-headed windows on the southern wall had iron frames reused from a nineteenth-century engine house. A miniature railway ran around the museum, past various objects such as boats, helicopters, locomotives, and cranes.

Despite playing a prominent role in the regeneration of Cardiff Bay in the second half of the twentieth century, the museum was closed and sold for £7.5m in 1998 after having failed to secure funding to move into the new Wales Millennium Centre (NPRN 403908). It was demolished shortly thereafter to make way for the development of Mermaid Quay (NPRN 422952). It has since taken on another form in the National Waterfront Museum, Swansea, which opened in 2005.

(Sources: Dobson, `Shops to Replace Ships as Maritime History Goes West?, Independent, 2.6.1998; `Tourism Hopes as New Museum Opens?, BBC News, 17.10.2005; Victorian Society Tour Notes, VS01/16; Newman, Buildings of Wales: Glamorgan (London: 1995), p. 267)
A.N. Coward, RCAHMW, 23.07.2018