The belfry alone, noted by the antiquarian Thomas Westropp in 1897 as disproportionately large for the church it serves, gives some sense of the ambition that went into a place so thoroughly surrounded by tidal water. Much of the outer walls are now lost to dense overgrowth, but the church, cloister, domestic ranges, and several medieval graveslabs remain, along with a holy well known as Tobernamonastragh about fifty-five metres to the south-west.

The abbey, dedicated to St Mary and known in older sources as Inisgad, was almost certainly founded on the site of an earlier monastery. It was included in a confirmation charter issued by Donal Mor O'Brien for Clare Abbey in 1189, placing it among a group of foundations established around the same period, alongside Inchicronan, Kilshanny, and Killone. The Augustinians were canons regular, meaning they followed a monastic rule while also serving pastoral functions, and the layout here reflects that life fully: a single-nave church oriented east to west, two side chapels, a cloister of plain piers and flagged sills, and a domestic south range containing a kitchen or refectory, barrel-vaulted cellar rooms whose construction involved wicker centring (a technique using woven rods as temporary shuttering for the vault), and a garderobe projecting from the south-east corner. A canon from Grenoble was appointed in 1418, but by 1426 he stood accused of misrepresentation by Diarmuid Mac Ghiolla Phádraig, and for roughly a century the Mac Ghiolla Phádraig family dominated the abbacy. Henry VIII dissolved the house and granted it to Donogh O'Brien in 1543, the year O'Brien was created Baron of Ibracken. By 1577 the property extended to four acres of arable land, fourteen of mountain and pasture, the abbey site itself, and several nearby islands. In 1712 Henry, 7th Earl of Thomond, granted it to Richard Henn.

The architectural detail still visible rewards close attention. Above the west door of the church, a two-light ogee-headed window retains its splayed ingoings and a heavy near-flat rear arch. Inside, a sedilia, the arched recess used by officiating clergy during Mass, survives on the south wall of the chancel with ogee hood mouldings and crocketed finials. The belfry, which Westropp assigned to the fifteenth century along with the chapels, has a vaulted basement with wicker centring and five storeys above; its stair reaches only the first floor, and the upper levels are now inaccessible. The cloister garth is noticeably off-square, and round arches cross the walk diagonally at each corner, resting on corbels that Westropp dated to the same century. The island setting means access requires planning, and much of the eastern domestic range is described as very heavily overgrown, but the church and cloister remain largely legible as a coherent monastic complex.