Known as Cell D, it sits on the north-eastern side of the better-preserved Cell C, and there is reason to believe it predates its neighbour, making it one of the oldest surviving remnants of the early medieval monastery perched on this Atlantic island off the Kerry coast. It is not the dramatic corbelled dome most people associate with Skellig Michael. The surviving remains offer no evidence that it was ever of corbelled construction at all, which quietly sets it apart from the cells that have made the site so recognisable.

A clochán is a small dry-stone building, typically associated with early Christian monastic settlements in Ireland, and Cell D is a modest example by any measure: roughly 2.5 metres by 2.3 metres internally, with walls standing to a maximum height of 2 metres at the north-west. Internally, the wall-face shows a basal row of upright slabs overlain by roughly coursed masonry, and the largely unflagged floor slopes down towards a conserved doorway just over a metre high. The structure is poorly preserved, and its history is complicated by later interventions. An annotation on a plan drawn by the Earl of Dunraven in 1875 indicates that portions of the external face at the north-east and south-east are of nineteenth-century date, while the rear external wall-face rests on a plinth that was rebuilt in the 1980s. The cell, in other words, carries the marks of several different hands across more than a thousand years, and unpicking which elements are original is not straightforward.