What makes it worth pausing over is the mixture of arch types built into its four spans: the two northern arches are segmental, meaning they rise from a shallow curve rather than a full semicircle, while the two southern arches are round-headed, and of differing sizes from one another. That asymmetry, quiet and easy to miss from a moving vehicle, speaks to a structure that was probably built or altered in stages rather than conceived as a single unified project.

The bridge runs south from Watergate Street and was, in the medieval period, the principal southern entry point into the town. A town gate stood immediately to its north, so anyone approaching Fethard from that direction would have crossed the water before passing through a controlled threshold into the settlement. The bridge itself is narrow, running 29 metres in length and just over five metres wide, and is built from roughly coursed limestone rubble. The parapet, standing about 1.37 metres high, has been capped with concrete at some point, which is the most visible sign of later intervention. On the western face, two triangular cut-waters project outward from the piers; these angled projections were a standard medieval engineering feature, designed to divide the current and reduce the pressure of water and debris against the bridge's supports.

Fethard is one of the better-preserved medieval walled towns in Ireland, and the bridge fits naturally into that context. Watergate Street, from which it extends, takes its name from the town's water gate, and the sequence of bridge, gate, and walled town would once have formed a coherent defensive and administrative boundary. The concrete capping on the parapet is an honest reminder that old structures get maintained with whatever materials are to hand, and the bridge remains in everyday use, which is perhaps the most straightforward explanation for why it has survived at all.