The two-storey rectangular structure, measuring approximately 6.6 metres north to south and 5 metres east to west, now forms the southwest corner of Rock Cottage farmyard. Though significantly altered through centuries of agricultural use, the building retains several telltale features of its defensive past.

The castle's original medieval character is still evident in its thick walls, which feature an external base batter; a common defensive element that helped deflect projectiles and made scaling more difficult. A narrow splayed window survives, designed to provide light whilst limiting vulnerability to attack. Perhaps the most intriguing architectural detail is the small rectangular corner tower on the southeast corner, measuring just 1.52 by 1.18 metres internally. This compact space preserves remains of a wicker-centred vault over its first floor, a construction technique where woven branches formed the framework for the vaulted ceiling.

The transformation from fortified residence to farm building represents a common fate for Ireland's tower houses, many of which found new life as agricultural structures when their defensive purpose became obsolete. Rock Castle's conversion likely saved it from complete ruin, though the modifications have obscured much of its original layout. Today, it stands as a modest but tangible link to the area's medieval past, when such fortified dwellings dotted the Cork coastline, serving as both homes and strongholds for local families.