Marine Protected Areas are important tools for the conservation and management of marine ecosystems, including top predators. The Namibian Islands' Marine Protected Area (NIMPA) primarily aims to improve the status of threatened seabird species breeding in Namibia and therefore needed to include all Namibian seabird breeding islands and key foraging areas. For the design of the NIMPA we used information on the foraging ecology of globally endangered African penguins Spheniscus demersus and locally endangered Cape gannets Morus capensis obtained in 2005 and 2006 from three breeding islands in Namibia using data logger technology. Additional data logger studies (2008-2010) were conducted on African penguins and globally endangered bank cormorants Phalacrocorax neglectus following the NIMPA's design phase to test the adequacy of its boundaries regarding foraging ranges. Foraging areas greatly overlapped with those identified previously and were located within the NIMPA. Foraging ranges of African penguins from Mercury (mean 21.5 ± 6.6 km) and Halifax Islands (mean 12.1 ± 7.0 km) as well as of bank cormorants from Mercury Island (mean 3.2 ± 2.2 km) fell within the boundaries of the NIMPA. The mean foraging range for Cape gannets from Mercury Island (103.5 ± 35.4 km) was only partly included; core feeding activities took place within the NIMPA boundaries. These results demonstrate that despite the initial paucity of data, the NIMPA's design was adequate in terms of encompassing key foraging areas of threatened seabirds and the use of preliminary data allowed the timely proclamation of the NIMPA while further studies were conducted to verify this. Keywords: Marine Protected Area, Reserve design, Threatened seabirds, Foraging ecology, Ecosystem health, Conservation.