Maritime Spatial Planning processes are already being implemented in many parts of the world being Europe one of the hot spots due to the approval of the Directive 2014/89/EU of the European Parliament and of the Council of 23 July 2014 establishing a framework for maritime spatial planning, which oblige every coastal Member State to have approved plans by March 2021. This Directive does not allocate specific funds for the development of these plans but it supports national processes by funding Maritime Spatial Planning transboundary projects among neighbouring countries. These projects have mainly two benefits, one is to provide states with knowledge, capacity and methodologies to apply in MSP national processes, and another one is to facilitate the coherence along plans of neighbouring countries sharing a sea basin region. As biological and ecological processes in the marine environment are not limited by administrative borders, the transboundary component of Maritime Spatial Planning is of extremely importance to manage marine resources in a sustainable way.