Llanychaer is a small village in NE Pembrokeshire, 2 miles SE of the port of Fishguard. St David's church is in the centre of the village, and was entirely rebuilt c.1876, possibly to the designs of E. Dolby (Glynne, 1898, 360). The church was built in the same location as its predecessor, on its foundations in fact, but retained none of the earlier fabric. Glynne (1898) published a print of the medieval church which is reproduced here. The present building consists of a 2-bay chancel, a 3-bay nave, a south transept and a lean-to vestry against the south wall of the chancel west bay and joining the transept east wall.

Construction is in squared, rusticated rubble throughout (possibly rhyolite according to Heneb) with ashlar quoins. The only feature surviving from the medieval church is the Romanesque font.

The church was a parish church in the post-Conquest period, in the deanery of Cemais (Rees (1932)). The medieval church was, according to Glynne, rebuilt on the old foundations in 1876. By 1872 it was 'fast hastening to decay’ and presented ‘a sad spectacle…the roof is dreadfully out of repair, the furniture ruinous and the church disused save for funerals’.