AbstractThe EU MSP Directive is an example of a so-called new generation directive, which gives Member States room for adaptation to national contexts. The main objective in this article is to identify and analyse potential obstacles to effective and efficient planning caused by the diversity among national MSP frameworks that the Directive's broad regulatory boundaries have led to. It is shown that planning approaches can differ substantially between neighbouring countries, which can make it challenging to coordinate across national borders. Divergence between national MSP frameworks can also emerge from how political, jurisdictional and, administrative systems and traditions are organised in different Member States. It is shown that neighbouring countries can diverge substantially in how the ecological, economic and social dimensions of sustainability are balanced, which can make transnational coordination challenging. Furthermore, it is shown that stakeholder consultations differ among Member States in terms of, for example, who were invited, how the consultations were undertaken, and the role they play in relation to political decision-making. Because of these, and other differences in how MSP frameworks are being developed in the Member States, it is suggested that regional integration should be promoted with discretion. From this perspective, it seems reasonable to embrace diversity, while simultaneously promoting the adaptive management of coordination problems at lower levels, when, or if, they emerge or can be foreseen. Thus, increased integration of national MSP frameworks should be viewed as an instrument to reduce concrete efficiency losses, rather than as an intrinsic good.