Several innovative ocean multi-use (MU) concepts that could contribute to a more sustainable and efficient use of ocean space have been proposed by the scientific and business community. There are yet very few of these MU concepts that are today implemented, mainly due to a lack of knowledge about potential impacts on the economy and the marine environment. MULTI-FRAME aims to increase the knowledge base and capacity of public and private actors for sustainable ocean MU, by providing concrete open source tools, assessment results and best practice examples. Results are expected to encourage relevant actors to systemically consider the MU concept in their planning and assessment practices and to streamline it in relevant ocean policies. Multi-Frame's co-development approach moves beyond the inherent limitations of theoretic research. A generic approach will be co-developed with a wide range of public, private, research and community actors and tested for the assessment of 1) cumulative and in-combination, 2) positive and negative, 3) socio-economic, cultural and environmental impacts of MU. Project will fine-tune this approach by building scenarios together with a wide range of relevant stakeholders in five vulnerable marine areas in Sweden, Mozambique, Norway, France and United States. These case studies will: assess potential impacts based on current evidence; allow for possible MU options to be explored; ensure transferability and adaptability to different environments; consider a multitude of marine sectors and governance systems. The development of the assessment approach and the scenarios will feed into the final product of MULTI-FRAME, the 'Ocean Multi-Use Toolkit', meant to assist planners when deciding on the most optimal combination of uses in a given marine space, taking into consideration an equitable distribution of possible benefits while avoiding, minimizing or mitigating negative impacts. The Toolkit will also aid the decision-making processes of authorities and businesses venturing into offshore activities or developments.