Holy Trinity church is situated in the northern angle of the triangle formed by the B4303, Farmer Row and Park View. The churchyard is bounded by Farmers Row on its west side and Park View on its east. It was erected in 1857 and consecrated in 1858. It was built in early Decorated style with a slightly Germanic character, to designs of R.K.Penson, its purpose to ease the burden on Llanelli's parish church, St Ellyw's (NPRN 12684). Holy Trinity became Felinfoel Parish Church some 21 years later. Most of the kerbstones were removed in the 1970s and the churchyard was extended to the south in 1990s when the site of the former garden of the National School was consecrated fora burial plot. The lychgate was restored in 1998.
The church is constructed of randomly coursed local sandstone with a lighter coloured stone door and window dressings and tracery. Ashlar stonework was used for the buttresses, quoins and porch gable copings. The roofs are steeply pitched with light-red tiling (restored), and small cast-iron apex-crosses at east and west. It has undergone little change since it was first built. In the1960s the roof was completely renovated, with the original stone spire being replaced by one of green copper.
The layout of the church is cruciform and consists of a central tower and spire, nave, chancel, and two short transepts. The chancel roof is lower than those of the nave and transepts. To the north of the chancel is a double-gabled vestry and to the south of the nave a porch. Inside, the aisleless interior is broad under a five-bay roof with arch- braced high-collar-beam trusses. The crossing is high and lit by high lancets, with two arch-braced beams supporting the bellchamber and spire. The chancel is short and wide with a three-bay roof with arch-braced collar beam trusses with V-struts above. The chancel floor is of mosaic with large tesserae. Fittings include oak altar with linenfold carving, and reredos with openwork top, both of 1950; the other fittings are by Penson. The stone pulpit at left of chancel arch is carved and painted, at the west of the nave is an octagonal font on four colonnettes. Stained glass includes work by Celtic Studios (1950).

Sources include:
www.llanelli-history.co.uk
Extracts from Cadw listing description.
T.Lloyd, J.Orbach & R.Scourfield, Buildings of Wales: Carmarthenshire and Ceredigion (2006), p191.

D Leighton & N Vousden, RCAHMW, 16 June 2015