This one, a slab nearly two metres tall from the Kilbonane area of County Kerry, carries three separate ogham inscriptions, running along both edges and down the face of the stone, and scholars have concluded that the texts on the angles are entirely independent of the one scratched across the face. Whether they were added at different times, by different hands, or for different purposes remains genuinely uncertain, not least because a repaired break across the middle of the stone has left part of the inscription unclear.

Ogham is an early medieval script used primarily in Ireland between roughly the fourth and seventh centuries, in which letters are represented by sets of notches and lines cut along the edge of a stone. The Kilbonane stone originally lay in the chancel of Kilbonane Church before being moved to Coolmagort, where it is now displayed alongside seven other ogham stones recovered from a nearby souterrain, an underground stone-lined passage typically associated with early Irish settlement sites. The scholar R.A.S. Macalister, whose readings of Irish ogham stones remain a standard reference, worked on this stone in both 1903 and 1945. He read the main face inscription as including the names MUIDAGNIESSICONIDDALA, AMIT, and BAIDAGNI, while the right-hand edge offered BAIDAGNI MAQI ADDILONA, and the left-hand edge NAGUNI MUCO BASIDANI. The name BAIDAGNI appears to recur across two of the three inscriptions, which is one of the details that makes the stone difficult to interpret straightforwardly. Macalister noted that the smaller line on the face, roughly half the length of the main inscription beside it, forms part of that facial text rather than belonging to either of the edge inscriptions.

The stone has more recently been digitised as part of the Ogham in 3D project run by the School of Celtic Studies at the Dublin Institute for Advanced Studies, which has produced detailed three-dimensional models of ogham stones across Ireland and Britain, allowing closer examination of inscriptions that are worn, damaged, or, as here, unusually complex in their layout.