It is over two metres long, tapered from head to foot, and broken in three places. The cross incised into its surface is barely visible now, worn to near-absence by time and perhaps by the damp of the island air. What survives is the ghost of a devotional object rather than a legible one.

The slab is a cross-slab, a recumbent carved stone of the kind used to mark graves or serve as a focus for veneration in early medieval and medieval Irish ecclesiastical sites. It measures roughly 2.1 metres in length and 0.2 metres in thickness, tapering from 0.7 metres wide at the top to 0.55 metres at the base, with a chamfered edge at that lower end. The incised cross has a shaft of around 1.5 metres and a transom of 0.55 metres, with what appear to be open terminals, though erosion may be responsible for that feature rather than original design intent. According to a 1995 architectural survey of Inisfallen Island by M. Weaver, it is comparable to what scholar Lionard identified as a Group 1 class of outline crosses. The date remains uncertain. The chamfer could indicate that the slab was carved as early as the ninth century with that decorative edge added later, though a twelfth or thirteenth-century date is considered more probable overall, placing it within the broader flourishing of Hiberno-Romanesque and early Gothic church culture in Munster.

Innisfallen itself is accessible only by boat from Killarney, which gives the island a particular quietness even in the tourist season. The abbey ruins are open to the air, and the cross-slab lies inside the chancel; knowing to look for it, and knowing what the faint incised lines represent, makes the difference between walking past a broken floor stone and recognising something that has occupied this spot, in one form or another, for the better part of a thousand years.