Roofless for centuries, spread across flat farmland on the north bank of the River Clare, the complex retains its nave and chancel church, a three-storey tower, a cloister garth, the footprint of domestic ranges, and even the remains of a watermill to the south. The north transept was still roofed around 1900 and had functioned as a Catholic chapel into the nineteenth century, a detail that speaks to the long, improvised afterlife of suppressed religious houses in Ireland.

The friary was already in existence around 1252, probably founded by John de Cogan I, and the fabric of the church spans several centuries of building, alteration, and rebuilding. The chancel, oriented east to west and running to around 43 metres in length, preserves six pairs of thirteenth-century lancet windows, narrow pointed openings set in opposing walls to draw light through the space. The large traceried window now filling the east gable is a fifteenth-century replacement for an earlier triple-lancet arrangement; the sills and jambs of those original openings are still partly visible beneath it. The north aisle, tower, and north transept are also likely fifteenth-century additions. Inside, the chancel's south wall carries a piscina, an aumbry, and sedilia, the shallow stone basin, cupboard, and bench-seating that served the priest during Mass, while the north wall holds a canopied tomb niche associated with the de Burgos, one of the great Norman-Irish dynasties of Connacht. The west gable had fallen by the early twentieth century, though it was still standing in 1792 and then contained a pointed arch doorway with a traceried window above.

The graveyard attached to the friary repays attention for an unusual reason: several of its tombstones carry occupational symbols, carved emblems that identify the trades of the deceased rather than relying on text alone. This was a reasonably common practice in early modern Ireland, particularly among craftsmen and merchants, but the concentration of examples here makes the Claregalway graves a particularly legible record of the working life of the community that gathered around what was once a medieval borough.