<p>Countries attempting to grow their ocean economies are encouraged to adopt the internationally recognised processes of marine spatial planning. Marine spatial planning encourages inclusive and sustainable management of ocean resources and spaces. However, producing a marine spatial plan that is considered socially inclusive and follows an ecosystem-based or sustainable approach is complicated and complex. Decision makers need to integrate the various needs, interests and knowledge from numerous sectors and stakeholders, which are often incompatible and competing for space to promote growth in socio-economic wealth and environmental health. Using decision support tools to produce future scenarios that explore the potential outcomes of decision-making is an excellent way to integrate large amounts of information into easily understood temporal and spatial outputs. Building scenarios, if developed through a bottom-up process (i.e., involving stakeholders from the start and throughout the process), can provide a platform that can promote the sharing and integration of different types of knowledge, thus producing more equitable and sustainable area-based plans. Here, we present a systematic method and use the prioritizR with zones tool to produce zoning scenarios for a high biodiversity-high human use bay (Algoa Bay) in South Africa. We show how win-win scenarios for ocean health and socio-economic priorities can be developed, from the bottom up, in an inclusive, ecosystem-based and transparent manner.</p>