Sandwich Harbour is a remote coastal wetland within Namib-Naukluft National Park, about 55 kilometres south of Walvis Bay. It lies where the Namib Desert meets the Atlantic Ocean, with tall dunes rising beside a lagoon, mudflats, and shallow coastal waters. The area is part of the Namib Sand Sea, where wind and ocean moisture shape one of the world's most distinctive desert environments. Access is generally by four-wheel-drive vehicle, as deep sand and changing coastal conditions make the route unsuitable for ordinary vehicles. The combination of dunes and wetlands gives Sandwich Harbour its distinctive landscape.

Sandwich Harbour also has a long human history. Archaeological sites in the area indicate human activity going back at least a thousand years, while later use included fishing, hunting, sealing, and guano collection. The Topnaar people maintain cultural connections with the wider Namib-Naukluft landscape, particularly along the Kuiseb River farther north. Remains from the harbour's former economic activities can still be found in the area. The coast also contains shipwreck remains, including the wreck of the Eagle, adding another layer to the history of this isolated stretch of Namibia's Atlantic shoreline.

The wetlands are the central natural feature of Sandwich Harbour, with two distinct wetland areas consisting of mudflats, shingle bars, and vegetation supported by groundwater and tidal influences. The site is recognized as a Ramsar Wetland of International Importance and is an important coastal habitat for wading birds. Species recorded in the area include Damara terns and chestnut-banded plovers, while the wider coastal environment supports other seabirds and shorebirds. Towering dunes provide a dramatic contrast to the flat wetlands, and guided four-wheel-drive excursions commonly follow the shoreline and climb selected dune routes.

Sandwich Harbour is especially notable for the way wildlife survives at the edge of an extremely dry desert. Coastal fog provides moisture for organisms living in the surrounding Namib, while the wetland supplies food and shelter for large numbers of birds. The area also supports specialized desert plants, including nara melons at the northern end of the wetland. There are no permanent restaurants or developed town facilities at Sandwich Harbour, so visitors normally explore it as a guided day trip from Walvis Bay. The remote setting, shifting dunes, tidal flats, and abundant birdlife make the site an important part of Namibia's coastal conservation landscape.