What makes the arrangement quietly curious is the small, two-storey tower tucked against the chancel's south wall, accessible only through a narrow flat-headed doorway, its upper floor apparently an afterthought added at some point after the tower itself was first built. The whole structure is a patchwork of decisions made across different centuries, with limestone and sandstone rubble mixed in the tower's construction and the windows repointed and partly reconstructed in modern times.

The church follows a nave-and-chancel plan, a common medieval layout in which a longer nave for the congregation connects to a smaller chancel reserved for the clergy and altar. It measures just over nineteen metres from east to west and just under eight metres across, with walls nearly a metre thick. Its institutional status shifted in 1458, when Cormac, the Bishop of Ardagh, elevated it from a dependent chapel to a parish church in its own right, a change recorded in the papal letters of that year. The nave itself may have been added at roughly this moment, giving the building a more substantial form befitting its new standing. The church sat approximately thirty metres south of an Augustinian priory on the same island, the two religious buildings occupying the same small landscape in what must have been a closely ordered monastic and parochial world. The chancel retains simple round-headed windows, and the one architectural feature singled out as late-medieval is a round-headed window whose restrained profile is typical of the period.