Doubtful Sound / Patea is a remote and expansive saltwater fiord located in Fiordland National Park, Southland, New Zealand. It stretches 40 kilometres from its head at Deep Cove to the Tasman Sea and is the deepest of New Zealand's fiords. Access for independent paddlers is extremely limited, as there is no road to the fiord. All visitor access requires a tour or charter service. The primary launch point for guided kayak tours is Deep Cove at the head of the sound, reached via a boat crossing of Lake Manapōuri followed by a bus transfer over Wilmot Pass. These tours, operated by small local companies, typically provide all gear and cater to all experience levels, with groups limited to around ten people. The fiord is characterized by its immense scale, sheer cliff faces, dense temperate rainforest, and numerous waterfalls, many of which are most active after rainfall. Its Māori name, Patea, translates to 'place of silence,' reflecting a profound sense of solitude and tranquility broken only by birdsong and cascading water. Wildlife encounters may include bottlenose dolphins, the southernmost population of which resides here, Fiordland crested penguins (tawaki), and New Zealand fur seals (kekeno). The fiord branches into several arms, such as Hall Arm and Crooked Arm, which provide sheltered exploration routes past dramatic scenery. Due to its exposure to the Tasman Sea and prevailing westerly winds noted by early explorers, conditions can be challenging, and paddling is often weather-dependent. The water is deep and cold year-round. There is significant commercial boat traffic from scenic cruise vessels and overnight charters, which must be factored into route planning. The overall paddling experience is one of wilderness immersion in a pristine, dramatic landscape that sees far fewer visitors than neighbouring Milford Sound.