What makes it slightly odd to the modern eye is that it is now a private dwelling, its military geometry absorbed into domestic life, its cannon pivot still sitting at the centre of a rooftop parapet designed to sweep the harbour approaches.

The tower is numbered 10 in the sequence of Martello towers built south of Dublin, a series of fourteen circular fortifications, along with several associated batteries, constructed to defend against the threat of Napoleonic invasion. Martello towers are thick-walled, flat-roofed cylindrical forts, a design developed from an Italian model and rolled out rapidly along the British and Irish coasts in the early nineteenth century. Work on the Dublin towers commenced in 1804 under the supervision of Colonel Benjamin Fisher of the Royal Engineers, and by December 1805 all were armed and complete. Tower No. 10 was built of coursed granite ashlar, its walls slightly tapered, or battered, as they rise to the parapet, and it measures 10.8 metres in diameter. Entry was always deliberately awkward: you approach from the west, climb an external wooden staircase to a first-floor doorway, and pass beneath a machicolation, an overhanging projection supported on five corbels through which defenders could drop objects or fire down on attackers below. Inside, the garrison room on the first floor has a vaulted ceiling rising to 3.6 metres, bow-shaped east and west walls, and a stone spiral staircase cut into the wall thickness. The roof retains its broad parapet and the central pivot point where a cannon would have been mounted. As Kerrigan noted in 1995, the tower sits in sight of both the Dalkey Island tower to the south-east and the more famous Sandycove tower, No. 11, to the north-west.

Because the tower sits on private property, it cannot be entered or closely inspected without permission. It is, however, visible from the vicinity of Bullock Harbour itself, a small working harbour in Dalkey that is easy to find and worth the short detour from the main coastal road. The surrounding low circular wall noted by Turner in 1983 is also part of the original structure. Those with a particular interest in the tower's fabric will find detailed architectural drawings in the planning records held by Dún Laoghaire-Rathdown County Council, submitted as part of a refurbishment application, and a military plan survives in the Irish Military Archives under reference E/MA/MPD/AD119454-008.