St Michael's Church is situated at the west end of the planned settlement of Cosheston, some 150m North of Cosheston Pill. The church site may be early medieval in origin. A possible hillfort (NPRN 422376). some 650m north-west of the church may be associated with the early church site. It was listed in the 1291 Taxatio. The church is just west of the post-Conquest planted nucleation of Cosheston. A curving earthwork noted in the field to the south of the churchyard may represent the boundary of a larger enclosure. The church was a parish church during the post-Conquest period, belonging to the Deanery of Pembroke. It is thought to have always been in the patronage of the Lords of the Manor of Cosheston.

The church is a Grade II listed building constructed of limestone rubble. It consists of long, 4-bayed chancel, 4-bayed nave, 3-bayed north aisle, south transept (with former skew passage) 2-storeyed west tower over the nave west bay, 3-bayed vestry north of the chancel west bays, and lean-to boilerhouse east of the vestry. The nave is thought to date to the 13th century. To the east of the south door is a possibly contemporary double recess with plain, 2-centred arches supported on a central corbel; appearing to represent a sedilia but possibly representing the well-head of a medieval baptistery. The nave's north and west walls have a medieval sloping basal batter. The chancel west bays, south transept, south porch and a former south transept are thought to be 14th-century. The porch wall may have featured a first floor parvis, as its east wall, featuring a plain, square, stoop recess, is very irregular. The west tower and north aisle are thought to be 16th century. The tower is similar to that at Minwear. The former spire had a weathervane dated 1781, which may be the date of an earlier restoration. The church was restored in the earlier 19th century (sometime after 1830), when the chancel was rebuilt and extended eastwards. The northern skew passage is thought to have been removed at this time and replaced with a small vestry. The church was again restored in 1885, when it was reroofed and a new vestry was built. Most of the openings date from this time. There is a blocked fireplace in the vestry east wall dating from that time, although the chimney has been removed. The boilerhouse was added sometime between 1885 and 1907.

Sources include:
Dyfed Archaeological Trust, 2000, Historic Churches Project, Pembrokeshire gazetteer
Dyfed Archaeological Trust, 2003, Early Medieval Ecclesiastical Sites Project, Pembrokeshire gazetteer

N Vousden, 21 November 2017