The Mahon River in County Waterford is rated Grade 4-5 and flows from the uplands near Mahon Falls down through a gorge before eventually reaching the sea at Bunmahon on the Copper Coast. The river offers distinctly different paddling characters depending on which section is run.

The upper section, beginning below the waterfall, is a demanding stretch of continuous rocks, boulders, undercuts, and other serious hazards. Every drop on this section requires scouting on each visit, as lines can change rapidly depending on rainfall. Pinning is a significant risk on the larger drops, and the deep bogs lining the banks complicate rescue and scouting efforts — the banks themselves can run like taps into the river during rain, causing water levels to rise quickly. Between the tree line and the gorge, the river becomes very shallow and heavily bushed, making scouting difficult; most paddlers bypass this stretch in favour of the gorge below, which is considered the highlight of the upper run. The gorge banks are extremely slippery, and strainers from trees are a persistent hazard throughout.

From Mahon Bridge on the R676, it is possible to paddle downstream to Kilmacthomas and continue on to Bunmahon provided water levels are adequate. This lower section is considerably more moderate, with the main features being a small weir behind Flavaghan's Factory and another weir within the public park in Kilmacthomas. Paddlers should be aware of water extraction works associated with the Ballyshonock Reservoir near Portlaw, located between Kilmacthomas and Bunmahon. The river meets the sea at the far end of Bunmahon strand, where tidal rips can present a hazard at the river mouth.

The area around Mahon Falls is a popular tourist destination, and paddlers are encouraged to park considerately with attention to bus access, and to keep the area clean. Copper Coast Kayak Adventures operates guided paddles on the river, offering a more relaxed experience of the waterway within the Copper Coast UNESCO Global Geopark.