St David's Church is situated within a quadrilateral churchyard, whose southern boundary is delineated by a stream, which appears to flow from holy well (NPRN 32489), which reputedly has healing powers and is located just to the east of the north-eastern corner of the churchyard. The church was mentioned as a `Dewi? church in a mid-twelfth century poem. The churchyard appears to be nuclear to an informal boundary system. A cross-incised stone (NPRN 276033), originally from Cilrhedyn Isaf, Parc-y-fynwent, now stands in the churchyard to the north-west of the church, at the west end of a railed enclosure. An inscribed stone, Llanychaer 1, was noted in 1698 on the north side of the church but is now lost. Its inscription is thought to date to the sixth century and its former presence here is the sole evidence for the early medieval origins of the site. The church was a parish church during the post-Conquest period, belonging to the Deanery of Cemais. It seems to have been mentioned as `Llanychaeth? in a twelfth century poem. The living was a rectory appendant to the Manor of Llanychaer in the Barony of Kemes.

The font, thought to date from the twelfth century and comprising square, scalloped bowl with cylindrical stem and square base, was retained from the earlier building. The current church was entirely rebuilt around 1876, possibly to designs of E. Dolby or possibly to the designs of R.J. Withers (sources differ). The church was built in the same location and on the same foundations as its predecessor, but retaining nothing from the earlier fabric. The current church is a Grade II listed building, constructed of squared, rusticated rubble (possibly rhyolite) with ashlar quoins. It consists of 3-bayed nave, 2-bayed chancel, south transept and lean-to vestry.

Sources include:
Cambria Archaeology, 2000, Pembrokeshire Churches, gazetteer, 48
Cambria Archaeology, 2003, Early Medieval Ecclesiastical Sites Project, Pembrokeshire gazetteer

N Vousden, 16 January 2018