Neath Mission Hall was built in 1903, initially as an extension of the earlier and adjoining Calvinistic Methodist Chapel, which had been built in 1884 by D.M. Davies, architect. The Mission Hall was built by the Forward Movement, which was the missionary wing of the Calvinistic Methodist Church that sought to evangelise the working classes of Cardiff and industrial South Wales, and was led by the Reverend John Pugh (1846-1907). The Movement had a strong following in Neath where Seth Joshua (1858-1925) and his brother Frank Joshua (1861-1920) had been evangelising since 1883. The building of the Mission Hall coincided with Frank Joshua’s ordination by the Calvinistic Methodists. The earlier chapel remained standing but subsequently declined in importance and is now known as the Lesser Hall.

Built in Arts-and-Crafts style, of red brick with stone dressings, lintel and sill bands. The front is divided into 3 bays by pilasters. In the centre bay is a pair of recessed doorways behind original iron gates and beneath keyed segmental heads with projecting hood moulds.

Above the sill band are foundation stones laid by several individuals, including John Pugh and Seth Joshua. At the upper level the central bay is filled with a wide 6-light window, which is continued by 3 windows in the outer bays to create a continuous glazed strip, helping to give the front a distinct secular character. There is a deep dentilled eaves under the roof.

The interior was designed as a single undivided space, but in the latter half of the 20th century an entrance vestibule and a second minister’s room were created inside the entrance. The interior has retained its original parquet floor, boarded wainscot and plastered wall, and the ceiling which has small round cast-iron ventilator grilles.

The main hall was never furnished with pews in order to maximise the number of people who could attend meetings, a feature that distinguishes mission halls from other non-conformist places of worship. However there are pews in the 3-sided raked gallery, which stands on cast-iron piers and has an ornate openwork cast-iron front. The gallery is reached by stairways in either side wall, close to the entrance.

In the main hall there is a raised dais, but the set fawr has been removed. There are raked pews for a choir behind the dais and, further behind in the recess, is an organ installed in memory of Frank Joshua, which has a name plate for Henry Salter & Sons, Neath.

The windows to either side of the organ recess have stained glass in memory of Frank Joshua, his brother Seth, and Dr R. Davies, who was pastor between 1926 and 1942.

The link between the Mission Hall and the Lesser Hall is top-lit with hipped lanterns, and has a quarry-tile floor and boarded wainscot.

The building is listed grade II for its architectural interest as a rare well-preserved example of a mission hall, retaining very good interior detail. It is also of special historical interest as one of the last remaining buildings erected by the Forward Movement, which had an important role to play in the evangelising of working-class communities in South Wales at the beginning of the twentieth century.