The Duddon in Westmorland and Furness is a coastal estuary, a significant tidal feature opening out toward Morecambe Bay and the Irish Sea. The estuary's north shore is formed by the Furness peninsula, with the town of Millom situated there just outside the Lake District National Park. The area where the estuary begins to open out is a location for kayaking and stand-up paddleboarding. Paddling here is a marine environment dominated by tidal rhythms, not river flow. The adjacent River Duddon, which feeds the estuary, has a section downstream from Seathwaite that is popular with canoeists and is graded as a Class 3 whitewater river, indicating a separate freshwater paddling opportunity distinct from the tidal estuary. The overall character of the Duddon Estuary is one of a broad, open coastal landscape where the river meets the sea. The aesthetic is defined by the surrounding fells and valley, with the Duddon Valley itself being a noted destination. The wider area is recognized for outdoor adventure and exploring nature.