The Afon Dwyryd is a tidal river and estuary in North Wales, flowing through a valley of rare Atlantic Oak woodland near Snowdonia. The river runs roughly east-west, with the estuary opening out toward Tremadog Bay. The total paddleable distance from Pont Briwet upstream to the bridge at the Oakley Hotel (where the A487 crosses the river) is approximately 7 km one way, making a 14 km return trip. The estuary section is rated Grade 3 for stand-up paddleboarding, meaning it is subject to tidal movements and exposed to wind, requiring weather and tide-time planning by more experienced paddlers.

There are three main access points. The first is at Pont Briwet (GR 619 382), near Llandecwyn Train Station, where there is small lay-by parking and shore access; trips from here should begin around 1–2 hours before high water. The second is at Bryn Mawr, from a lay-by on the south side of the A487 (GR 649 601), where the carry to the river is only about 15 metres; this point allows paddling both upstream and downstream. The third is approximately 100 metres west of the Oakley Hotel, again from a lay-by on the south side of the A487 (GR 658 605). No access charges or permits are reported as required.

Tidal planning is essential. The east-flowing (flood) stream begins around 3 hours 15 minutes after high water Liverpool and continues to run for a further hour in the gorge section upstream of Pont Briwet. The west-flowing (ebb) stream begins around 2 hours 45 minutes before high water Liverpool. Tidal streams rarely exceed 2 knots. High and low water at Borth-y-Gest occur approximately 2 hours 45 minutes before Liverpool.

The river passes alongside the Gwaith Powdwr Nature Reserve, a former explosives factory now owned by the National Trust and home to nesting redstarts, tree pipits, pied flycatchers, and horseshoe bats. The steep valley slopes are covered predominantly by oak woodland, including the Coed Felenrhyd and Llennyrch woodlands, which form part of one of the UK's rare Atlantic Rainforests. The river remains close to the A487 for much of its length, meaning help is rarely far away. There is a campsite on the banks of the Dwyryd upstream from the tidal limit near Maentwrog at Llechrwd Riverside Camping Site (tel. 01766 590240).