A nave and chancel church with a Romanesque doorway and blind arcade on the W wall. Some Romanesque masonry is found under two windows on the N wall. Two small square niches in the NE corner may be Romanesque. The present layout of the church dates from the 13thc. there is a triple lancet window in the E wall and nine slender windows in the S wall. The remains of a triple sedilia are found on the S wall of the chancel.

The site was founded by St Brendan of Clonfert. The earliest historical references date from the 11thc. In 1068 Clonfert was vacated and its seniors came into W Munster (Annals of Inisfallen). Stone church wrecked by lightning in 1046 (Annals of Inisfallen). Ratass was chosen as the centre of the diocese of Kerry at the Synod of Rathbreasail, but Ardfert appears as diocesan centre in 1117, when Anmchad O hAnmchada Bishop of Ardfert, died (Annals of the Four Masters). In 1152 Mael Brennain O Ronain was present as bishop of Kerry at the synod of Kells; he died in 1166 and was buried at Ardfert (Annals of the Four Masters).

Leask identifies the Ardfert facade as a derivative of Cormac's Chapel, Cashel. O'Keeffe suggests sources in the W of England (but also possibly from western France (2003, 180, 318), and a date prior to Cashel, in the 1120s.)

Since this site was recorded (in 1992) the area around the W doorway has been conserved and restored.