This one sits inside a lake. At Gougane Barra in County Cork, a rectangular drystone enclosure built directly into the lakebed retains the water of the well, keeping it distinct from the surrounding lake. A flight of steps approaches it from the west, and a stone flag covers the opening. The structure sits on the eastern side of the causeway that connects the mainland to a small island containing a hermitage, so that anyone crossing to the island passes it almost at the threshold.

The site is associated with two separate feast days, suggesting a long continuity of use. St John's Day on the 24th of June drew devotions at the well in the early nineteenth century, and the antiquarian T. Crofton Croker, writing in 1824, left what is described as a colourful account of those observances. St Finbar's Day on the 25th of September is also marked here. Finbar, the sixth-century founder and patron saint of Cork, is traditionally linked to Gougane Barra as a place of retreat and contemplation before he established his monastery further downstream on the Lee, so the well belongs to a landscape already layered with early Christian significance. The well is still in active use as part of pilgrimage to the broader site, which means it has remained a living tradition rather than a purely archaeological one.