In a continuation of the previous research published in Ocean and Coastal Management, titled “An authority for marine spatial planning (MSP): a systemic review”, this research aims to name the Marine Spatial Planning (MSP) management authority most capable of overcoming some of the numerous MSP implementation challenges faced worldwide. The modified Delphi method and the Soft Systems Methodology (SSM) were employed to posit the following questions: What characteristics should an MSP management authority possess? What level of governance should a MSP management authority possess in order to effectively coordinate and communicate with national, regional, and international bodies? Which authority, from the authorities already involved in MSP planning and implementation, best meets the proposed requirements? An analysis of the results from first few steps of the SSM helped elucidate the characteristics necessary of an effective MSP management authority. This information was then shared, via Google forms, with a panel of experts chosen to participate in our modified Delphi method-based questionnaires. The results of our study indicate that national-level Maritime Authorities (MAs) are best suited to act as the MSP management authority. It is, therefore, of paramount importance that governments entrust MAs with the duties of planning and nationally implementing MSP. Taking into consideration that MAs fulfil most, if not all, of the characteristics required of an effective MSP management authority, it would seem to be the most obvious choice.