A Romanesque nave and chancel church located NW of the cathedral. Only the nave survives. It has columns at the external angles, and a cornice and corbels along the S facade. Some carved and moulded stones have been reused in the upper W and S facades. The S window has unusual floral decoration on interior and exterior. The chancel arch has lost its inner order but retains two outer orders with chevron on the arch. There is a round-headed W doorway with a decorated label. The N window of the nave has a round-headed chamfered exterior and a square interior opening. the W facade has a splayed flat-headed window.

The walls are of rubble, mostly limestone, and the carved stone is of red sandstone. At the NE angle only one section of the angle column remains, keyed into the angle of the walls, while the rest has been rebuilt in limestone with squared quoins.

The church was founded by St Brendan of Clonfert. The earliest historical references date from the 11thc (1031, 1032). In 1046 its stone church was wrecked by lightning. At the Synod of Rathbreasail, Ratass was chosen as the centre of the diocese of Kerry, but in 1117 Ardfert appears as the centre of the diocese 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 describes the W doorway as having two animal head stops (Leask, 1955, 155). He also describes curved chevrons on both faces of the second order of the chancel arch. He suggests that the arch originally had three orders and was c. 3.75 m in width.

The pattern found on the chancel arch imposts, of triple leaves in triangular panels is similar to a motif found at Donaghmore (Meath) and Clonfert (Galway).