The route starts on the R671 at the south end of the Gashouse Bridge in Clonmel, heading eastward away from the town and into County Waterford. As might be expected, the standard of the road on this side of the Suir is lower than that of National road on the other, with several more sharp turns. Briefly passing back into County Tipperary, it runs through the south side of Carrick on Suir – where the castle can be seen on the other side of the river. The road then turns southward, still following the Suir, to reach the western suburbs of Waterford, crossing the N25 at a roundabout.
The R680 now turns to run east into the town centre, crossing the Outer Ring Road and passing the old Waterford Crystal factory before arriving in the city centre. A zig-zag course brings it to the south side of the Rice Bridge over the Suir, which the R680 then crosses, to terminate in front of Plunkett Station.
Waterford Quays. Once the N25, now the R680
The R680 originally ended on the former route of the N25 at Kilmeadan. After the opening of the Waterford Bypass, it took over most of the old road as far as the Rice Bridge.