There is an increasing recognition that biodiversity conservation and development should be integrated in order to achieve both objectives. However, there is limited evidence to suggest how the two should practically be integrated. There is also increasing recognition that development is one of the direct drivers of biodiversity loss, habitat loss, and changes to ecosystem services. While reflecting on these issues (the absence of practical evidence of the integration and the adverse impacts of development on nature conservation), the management of protected areas (PAs) in many countries is often under pressure from development, trying to minimise losses of biodiversity that come from development. This paper examines development pressures in and around PAs in Tanzania and highlights the underlying social, economic and political causes of such pressures. It explores these using Saadani National Park (SANAPA) as a case study, with a multiple-method approach of qualitative research based on: in-depth semi-structured interviews; informal discussions; document analysis; and two months of field observations, coupled with the researcher’s experience with the wider community in the country and PAs in general. The findings show that the management of SANAPA is in conflict with the investors in the area and local communities over development pressures on biodiversity conservation in and around the park. The pressures of development come from: transport infrastructure development in and around the park, the proposed sugarcane plantation adjacent to the park, as well as sea-salt works in and around the park. The root causes of such pressures revolve around the government’s struggle to balance biodiversity conservation and socio-economic development, reflected in conflicting interests and lack of collaboration among government institutions, and coupled with poverty as well as ignorance of local communities. The findings, however, provide evidence for the need to design practical integration of conservation and development in order to achieve both objectives. They are, thus, crucial when internalising development concerns into conservation and designing practical integration in the context of Tanzania’s PAs management or elsewhere.