Although the sequence runs from 1 to 16, there were in fact only fourteen towers, because two of those numbered positions mark batteries alone, with no tower attached. Tower No. 14 at Seapoint is one of the fourteen that does exist, a free-standing circular structure of dressed granite sitting on a small promontory to the south-east of Seapoint railway station, looking out across Dublin Bay.

Martello towers are squat, thick-walled coastal defence structures, typically circular in plan, built across the British Isles and Ireland in response to the threat of Napoleonic invasion. Construction of the Dublin-area towers and their associated batteries began in 1804, overseen by Colonel Benjamin Fisher of the Royal Engineers. By December 1805, all towers in the series were armed and operational. Seapoint's tower was recorded by military historian Paul Kerrigan as a standard example, fitted for a single 18-pounder gun. Several details of its construction reward a closer look: the entrance sits above ground-floor level, reached by stairs, and above the doorway on the north-west side there is a machicolation, a projecting gallery through which defenders could drop stones or other materials onto anyone attempting to force the door. A double offset string course, a projecting horizontal band in the stonework, marks the parapet level, giving the tower its characteristic profile.

Access to the tower is from Brighton Vale Road, which leads down toward the sea. The site sits on an east-facing slope, so the light is generally best in the morning. The tower itself is not open to the public, but it can be observed closely from outside. Visitors approaching from Seapoint DART station will find it a short walk to the south-east. Taylor's map of 1816, produced just over a decade after the towers were completed, records the structure's position clearly, and the surrounding coastline has changed relatively little in outline since then.