St David's Church sits below and to the east of the triangular summit of a prominent coastal hill which has been suggested as a possible Iron Age hillfort (NPRN 419561). Royal Commission aerial reconaissance during the drought summer of 2013 appears to verify this, highlighting the parched banks and ditches of a large triangular or pear-shaped hilltop enclosure, generally following the lines of present field boundaries and walls but of more massive construction, suggesting a prehistoric origin. On the east side of the ridge is a discrete, smaller rectangular earthwork enclosure within the larger one, following the line of the ridge but with a rounded southern end, into which the churchyard encroaches. Six Early Christian Monument fragments are said to have been recovered from the fabric of church during nineteenth century restoration, but three have been lost. Llanddewi Aber-arth 1 (thought to date from the late ninth to early tenth century) consists of two fragments, with a diagonally set pattern of square frets and an interlace pattern similar to that on Silian 2 (NPRN 275650) at St Sulien's Church, Silian (NPRN 402554). The stone was also carved with two lengthy Latin inscriptions, of which only the end of each line survives. Llanddewi Aber-arth 1 is thought to have originally been part of the shaft of an elaborate free-standing cross. Llanddewi Aber-arth 2 is a mid to late tenth century hogback grave-cover. According to Nash-Williams, the hogback stone 'is the only example of the type in Wales from the 10th-11th century. It measures 10 x 24? x 10? inches. The church was a parish church during the medieval period, belonging to the Deanery of Ultra-Aeron. At that time the benefice was a prebend of St Davids Cathedral. The church was listed, as 'Aberaith', in the `Taxatio' of 1291. In 1833 the living was a perpetual curacy in the patronage of the Prebendary. In 1998 the living was a vicarage held with Henfynyw and Aberaeron. Buried in the churchyard are Rev. Alban Thomas Jones (died 1819) and his wife (died 1830), founders of Aberaeron.

The church is a Grdae II listed building, constructed of limestone and shale rubble. It consists of three-bayed nave, two-bayed chancel and three-storey west tower. The tower is thought to possibly be late fourteenth century in date. In 1896 it was noted that the church's pre-1860s walls had been over 1m deep. There are two marble plaques to Jane Jones (died 1787) and Henry Jones (died 1794) of Ty Glyn (NPRN 35324). The church was rebuilt in 1860-1862, to the designs of David Williams, Llanon. All walls except those of the tower are thought to have been demolished and rebuilt at this time. The church was again restored in 1883, when the present walls may have been laid. The pews, stalls and pulpit may also date to this time. The oolite font dates from 1888. The church was reroofed in 1931, to the design of W. Ellery Anderson, Cheltenham. The alter table dates from 1968.

Sources include:
Cadw, Listed Buildings Database
Cambria Archaeology, 2000, Ceredigion Churches, gazetteer, 48
Edwards, N. 2007, A Corpus of Early Medieval Inscribed Stones and Stone Sculpture in Wales: Volume II South-West Wales

RCAHMW, 2 December 2013