St Celynin's Church was first mentioned in documents of 1254. It is situated within a rectilinear churchyard which is located some 100m east of the foreshore. The remains of a stone fish trap (NPRN 409087) are situated in the intertidal area immediately below the church, and the two may be associated. The churchyard wall was rebuilt in 1884, but the lychgate (NPRN 43848) is thought to be earlier.

The church is a Grade I listed building, and retains much of its medieval character, having only been subject to minor nineteenth and twentieth century restoration. The original church may have been smaller than the present building. The building is constructed of roughly dressed local stone under a slate gabled roof. It consists of a continuous nave and chancel, and south porch with bellcote. Measurements are given as thirty yards by seven yards. There are two arched recesses either side of the alter. The building underwent extensive restoration in the late fifteenth or early sixteenth century. At this time the walls were raised and the building may have been extended to the west. The steeply pitched roof was also replaced at this time. Dendrochronological dating has produced a felling date range for the roof of 1502-1539. Visible traces of the old roof were reported in 1917 in the western gable. The porch and bellcote are seventeenth century, with the bell inscribed with the date 1660. The slit in the south wall would have provided lighting for a rood loft or stair. The present chancel screen incorporates elements of a late medieval rood screen. Seventeenth century wall paintings were found on the north wall of the chancel in 2003, including texts and a momento mori skeletal figure. The font is octagonal. A virtually complete set of benches date from about 1823. Of simple design, these benches not only record the names and addresses of their occupants, but include a complete social hierarchy from the vicar and gentry to the servants benches, giving a fascinating insight into local nineteenth century social history. After a period of some fifty years of abandonment, the building was carefully restored and reopened in 1917. The church is now disused.

Sources include:
CADW listed buildings database; History of Merioneth II (2001), 360-1.
Gwynedd Archaeological Trust, 2000, Historic Churches of Gwynedd: Gazetteer of Churches, report 391

RCAHMW, 8 November 2007.