St Thomas's church is situated in a prominent position in the centre of St. Thomas between Lewis Street and Maes Street, just south of Delhi Street. It was built in 1886-90 in Early English style by Thomas Nicholson of Hereford, at the expense of the Grenfell family of Maesteg House, Kilvey, and Taplow court, Buckinghamshire, leading industrialists in Cornwall and Swansea.

The church is constructed of snecked Pennant sandstone with Bath stone dressings. It consists of nave with lean-to aisles, lower chancel with side chapels, north-east tower with stone broach spire, and lean-to west porch. Inside, the porch has flat beamed ceiling. The tall nave with scissor-rafter roof forms a six-sided profile, the chancel roof ornamented with brattished wallplate and panelling over the sanctuary.

The interior colouring is unusual: the chancel arch on triple black-marble shafts, the chapel arcades given piers, caps and hoods of red sandstone but with arches of Bath stone. The east window has five graded lancets, their rere-arches carried on black marble shafts. The arcading is in red sandstone with black shafts below. Fittings include a carved ashlar font and an ornate Caen stone octagonal pulpit given in memory of Pascoe St Leger Grenfell. Stained glass includes works by Jones & Willis (1894) and Celtic Studios (1972 & 1978).

Sources:
Extracts from Cadw Listing description; J.Newman, Buildings of Wales: Glamorgan (1995), p.616.

RCAHMW, 22 May 2015

The church has undergone a program of refurbishment in 2020 which includes:

• Mezzanine second floor

• New community café

• Accommodation for a Food Bank, Credit Union and Baby Basics social outreach projects

• On site toilets including a shower facility for the Night Shelter

• Under-floor heating