Spatial decision-support tools can guide decision-makers towards knowledge-based spatial planning. Their application for multiple-objective zoning is beneficial for supporting the on-going Maritime Spatial Planning (MSP) process, in particular in areas of high density of uses like the Adriatic-Ionian region (AIR). In this work, we give contribution to the sustainable development of the aquaculture, as one of the main maritime activities for sustainable Blue Growth in the AIR. Aquaculture expansion should occur alongside the protection of biodiversity and the conservation of sites where aquaculture and its synergic uses can coexist. Planning for these objectives independently from one another has been shown to produce inefficiencies in costs, area, and conflicts across sectors. The objective of this research is to operationalize multi-objective zoning for aquaculture expansion and biodiversity protection (seabed habitats, marine mammals, seabirds and turtles species distribution, nursery and spawning areas of commercially important fish species). The area of analyses is the coastal area of the Emilia Romagna Region (Italian Northern Adriatic Sea). This area is the main producer of mussels in Italy and it is currently intensively crowded by several maritime uses, which are expected to grow over next years resulting in increase of conflicts and pressures on sensitive environments (Natura 2000 sites; Biological Protection zone). The decision support tool Marxan and its advanced version Marxan with Zones were applied to develop planning scenarios. Firstly, we prioritise biodiversity conservation, through Marxan, while minimizing conflicts with other anthropic uses. Secondly, we carry out an aquaculture suitability analysis using a multicriteria evaluation approach based on environmental, biological and socio-economic conditions. Next, we simultaneously prioritize both aquaculture and biodiversity, through Marxan with Zones, while minimizing impacts on seven other industries operating in the Emilia Romagna Region. We discuss an integrated zoning plan that meets targets for multiple objectives, and which adheres to several constraints regarding the location of aquaculture farms offshore in order to both allow the use of bigger technologies for mussel catch and minimize the impacts on coastal environments (pollution impact, visual impact). Our analysis can guide multiple stakeholders and decision-makers towards cost-efficient solutions that are scientifically based, thus contributing to the marine spatial planning process and sustainable growth in the Adriatic-Ionian region.