Interior
Nave and chancel have a queen-post roof of 11 narrow bays, with half bays at the ends. The S wall has 6 blind arches, as if intended for a S aisle. The 6-bay N arcade, of which the end bays are blind, has pointed arches with 2 orders of continuous chamfer. The king-post aisle roof has 7 narrow bays with half bays at the ends, and blind arches in its N wall similar to the nave and chancel. The chancel E wall is more elaborately treated, in C13 style. It has a corbelled ledge behind the altar which is flanked by 3-bay blind arcades with cusped arches and marble shafts. The E window has a rere-arch with similar shafts, and is flanked by single blind bays. In the S wall is a cusped and hooded piscina.
The octagonal Perpendicular style font has panelled stem and underside of bowl, and quatrefoils around the bowl. Pews have simple moulded ends and stalls have similar moulded ends, some with poppy heads. The wooden polygonal pulpit stands on posts and is decorated with blind cusped arches. The communion rail has scrolled iron uprights and wooden rail. The W wall has painted wooden boards with Creed, Lord's Prayer and Decalogue.
There are numerous memorials, the earliest of which is a medieval grave slab placed by the font. In the chancel N wall is a memorial to Bishop Richard Davies, signed by Edward Davies of London, although the relief carving is said to have been undertaken by William Thomas of Merthyr Tydfil. It has a high-relief portrait over an inscription panel. In the chancel S wall is a Gothic style wall tablet by John Thomas & Son of Brecon, to Elizabeth Johnes (d 1842). Pinnacled shafts flank a cusped inscription panel. Next to it is a classical style memorial with sarcophagus surmounted by an urn, to the Rev David Davies (d 1831), by Daniel Mainwaring of Carmarthen.
In the nave S wall is a monument to John and Mary Griffith (d 1722, 1738) erected by their daughter, an inscription panel supported by a cherub and surmounted by a broken segmental pediment and coat of arms. A simple marble scroll on a polished granite background, commemorates John Ryle Morris (d 1897). Next is a sarcophagus on a slate background to George Vaughan Philipps (d 1873), by William Davies of Carmarthen. A brass cross enriched with foliage decoration is to Rev Thomas Thomas (d 1881), next to which is a simple pedimented inscription panel on a slate background, to William Morris (d 1930).
In the aisle, the W wall has a slate inscription panel to Sybill Phillipps (d 1671), with a freestone surround with relief decoration. On the N wall are 3 memorials by James Foster of Bristol, with lozenge-shaped slate backgrounds to inscription panels surmounted by urns, to Thomas Blome (d 1810), Ann Blome (d 1807) and Herbert Lloyd (d 1806). A neo-classical style mourner and urn commemorates Mary Anne Lloyd (d 1861) and family, by G. Maile of London. At the E end of the aisle is the pew of the Philipps family of Cwmgwili. The largest memorial, in the E wall, has a classical surround with Corinthian columns and open segmental pediment above cherubs, surmounted by further cherubs and coat of arms, but no longer legible. To its R is a classical tablet surmounted by a draped urn, on a slate background, to John George Philipps (d 1816), by Daniel Mainwaring. A plainer inscription tablet of a polished granite background, commemorates Sir Grismond Picton Philipps (d 1967). In the N wall is a memorial erected by Captain J G Philipps in 1854 in memory of 3 of his sons, by Evan Harries of Carmarthen, on a slate background by David James of Carmarthen. Above it is an inscription panel with urn to Frederic Philipps (d 1838), also by David James.
Several windows have stained glass. The E window shows the Life of Christ, c1879. The chancel SE window shows Christ with Simon Peter. It commemorates Captain J G Philipps of Cwmgwili, said to have been the longest-lived survivor of the Battle of the Nile. The chancel SW window depicts the Resurrection, c1847. In the nave S wall, beginning at the E end, is 'Suffer little children', Christ as the Good Shepherd, while the W window has symbols including Agnus Dei and Dove of Peace. The N aisle E window, above the Cwmgwili pew, is Christ attending the sick, in memory of Grismond Philipps (d 1850).