St Ishmael's Church is sited some 40m from the high water mark, to the immediate east of a road and adjacent railway line which run parallel to the foreshore. St Ishmael's was a parish church in the medieval period, belonging to the Deanery of Kidwelly, and was first mentioned in documents of 1115. At this time it was granted to Sherborne abbey in Dorset, of which the Benedictine St Mary's Priory (now St Mary's Church, NPRN 301847) at Kidwelly was a cell. The grant was confirmed in 1303 (although it is thought that the church had also been granted to Gloucester Cathedral in 1141). The advowson was granted to the Bishop of St Davids in 1368 by John of Gaunt (Duke of Lancaster). After the dissolution it is thought that the advowson fell to the Crown. In 1609 the vicarage was in the tenure of Oliver Godfrey. In 1833 the living was a discharged vicarage in the patronage of the king. In 1998 the church was a parish church belonging to the Rural Deanery of Cydweli. The remains of a deserted medieval settlement (NPRN 15229), are buried in sand dunes on the edge of the foreshore, 400m south-west of the church. The Old Vicarge is located some 40m south of the churchyard. The original Vicarage was a much larger, six-bayed eighteenth century building, considered the finest in the county. however, it was destroyed by a stray bomb in 1940, which also reportedly left scars on the church.

The church is a Grade II listed building, constructed of limestone rubble with yellow oolite dressings (from 1859-1860). It consists of four-bayed nave and two-bayed chancel, north chapel and three-bayed north aisle, south transept (now vestry) with skew passage and two-storey saddleback south tower (was south porch). The nave and chancel may date to the thirteenth century. Although the chancel is now open to the nave, traces of a former respond for a chancel arch may be visible on the north wall. The former south porch is thought to date to the fourteenth century. The south transept dates to the fourteenth-fifteenth century, and the northern half of its west wall may have been part of the east wall of a former, larger south porch (an external recess may reflect this). An irregular arch (earlier than that between the nave and north aisle) leads from nave to south transept. The south transept communicates with the chancel via a plain, vaulted skew passage with square-headed opening at each end. The north aisle dates to the earlier fifteenth century, and communicates with the nave through a three-bayed arcade of arches like that between the aisle and the chancel's west bay. The chapel dates to the later fifteenth century, and there are marked burials (and possibly burial vaults) beneath its floor. The tower dates to the sixteenth century, and comprises a saddlebacked belfry stage over a porch. Crude rectangular openings in each of the four walls date from the sixteenth century. A wall tablet in the north wall of the chancel commemorates Catherine Mansel (died 1631), and displays a coat of arms. It comprises a slate inscription panel in a freestone surround with painted cherubs' heads, flowers, and column-caps. The church was restored in Gothic style in 1859-1860, and a triangular opening was inserted high in the tower's west gable. The church was re-floored, nave, chancel and chapel were re-roofed, and the south door was rebuilt. A fireplace (occupying a shallow, square buttress) in the south transept's east wall dates to this time, as does the conversion of the transept to a vestry. The pews and pulpit also date to this time.

Sources include:
Cadw, Listed Buildings Database
Cambria Archaeology, 2000, Carmarthenshire Churches, gazetteer, 48

N Vousden, RCAHMW, 29 January 2013