Whilst the Sustainable Development Goal (SDG) 14 promotes the conservation and sustainable use of the seas, oceans and marine resources for sustainable development, decisions in ecosystem-based Maritime Spatial Planning (MSP) follow annoying and costly trade-offs and this may negatively impact its acceptance. To address conflicts and cumulative impacts and favor, as much as possible, interfering of marine activities, positive coordination and win-win options, it is necessary to develop integrated and cohesive planning approaches and new management tools. In this article, a conceptual framework of “maritime cohesion” is being developed mostly applicable to peopled and crowded seas and a set of relevant indicators to assess it, is proposed. It is based on the triple-model of interdependent components such as “maritime spatial efficiency”, “maritime spatial quality” and “maritime spatial identity”, taking into account the “territorial cohesion” equivalent, promoted by the Cohesion Policy. Then, in order to broadly analyze the “spatial efficiency” component, the “multi-use” concept and management tools, recently given particular emphasis by EU Blue Growth Strategy, are examined thoroughly, using the relevant literature. This article highlights constructive use of “maritime cohesion” with the multi-use MSP paradigm as key part of “maritime cohesion” narrative and posits that its huge and extensive potential can stimulate dynamic, collaborative, cohesive and assemblage thinking in the MSP process and be the “spearhead” to balance economic, social, environmental and cultural aspirations in maritime planning to achieve sustainability in the marine realm.