The rectangular structure, measuring roughly 8.35 metres north to south and 10.05 metres east to west, was built from roughly coursed stonework bound with lime mortar. Its slightly battered walls rise from what appears to be a 19th-century courtyard, partially enclosed by deteriorating walls from the same period. The main entrance, located off-centre in the eastern wall, leads through a short lobby covered by a murder hole; a defensive feature that allowed defenders to attack intruders from above. From here, one door leads to the ground floor chamber whilst another accesses the spiral staircase that winds clockwise through the building.

The tower's interior reveals the careful planning of its medieval builders. The ground floor chamber, measuring 5.8 by 3.85 metres, features a rounded vault running east to west and was originally lit by a single window in the northern wall. As you ascend the spiral stairs, lit by narrow slit windows, you reach the first floor through a round-arched door into another lobby with its own murder hole. This level contains both a garderobe chamber with two later gunloop insertions and a main chamber that once boasted windows in three walls, though these are now heavily damaged. The second floor served as an entresol under a wicker-centred vault, now collapsed except for its springing courses, whilst the third floor's single chamber displays five windows, including one in the northern wall with an elegant double ogee-headed light, though its mullion has long since vanished.

The castle's strategic importance evolved through the centuries, from its origins as a stronghold of the MacMahon family to its various incarnations under English rule. In 1572, it was recorded as belonging to the Knight of Glin, before passing through several English hands during the Munster Plantation, including George Beston, Lancelot Bostocke, and eventually William Carter in 1592. During the Napoleonic Wars, a single-storey artillery blockhouse was constructed against the tower's western wall, featuring three stone-vaulted apartments that served as a battery covering the Shannon estuary. The site later found new purpose as a coast guard station in the 19th century, with records from 1863 noting its use alongside mentions of a nearby ancient burial ground. Today, whilst the structure shows significant wear, including a badly split eastern side and missing battlements, it remains an evocative reminder of the layers of history that have shaped this stretch of the Limerick coastline.