The World Bank defines the Blue Economy as the sustainable and integrated development of economic sectors in healthy oceans. It is a framework to realize the Sustainable Development Goals (SDGs), address climate change, protect biodiversity, and promote shared prosperity for all. Marine spatial planning (MSP) provides a needed comprehensive and integrated investment framework for the public and private sectors by dealing with upstream environmental and social issues and by giving certainty to investors to access areas and resources. The World Bank and many of its client countries are increasingly interested in using MSP to develop their marine sectors and are adding it to their investment portfolios. However, among staff and clients there is limited understanding of the process and how to use it as an investment framework. This guidance note seeks to close these knowledge gaps. MSP for Green Resilient and Inclusive Development (GRID) Marine spatial planning can help public and private marine sectors should contribute to green and inclusive development (GRID). MSP has special utility in targeting financial and technical support to governments and the private sector and providing the f inancial and social rational for investing in the Blue Economy. MSP primarily identifies integrated investment opportunities. The World Bank is well placed to help clients take advantage of MSP investment opportunities in pursuing recovery from COVID (and other economic or climate shocks) and in the general development of marine sectors. The World Bank has a range of tools for both public and private investments: financing instruments, convening services, and technical expertise. MSP can in turn support the World Bank, clients, and partners in tracking SDG progress, ensuring that safeguards are met, and reaching corporate, climate, biodiversity, and gender goals (See Volume 2 for further details). MSP: Guiding Blue Economy Investing . This guidance note examines the most productive ways to integrate MSP into World Bank projects and operations, and helps client countries invest in MSP. MSP is a process, not necessarily linear, and with cross-cutting considerations at each step. The key steps are: (1) making the case, (2) creating the enabling conditions, (3) formulating the plan, and (4) implementing the plan (Figure 1). Entry points can enable discussions on the benefits of MSP. Benefits go beyond an increase in wealth. They can include enhanced climate resilience, biodiversity, and reduction of pollution. MSP entails a major shift from managing marine resources on a sector-by-sector basis to taking an integrated approach. This requires changes in the distribution of government financial and human resources. Governments may see the changes as too costly, while the private sector may feel MSP is too high of an investment risk. Addressing these concerns up front can create entry points to explore MSP investments that will advance a Blue Economy. Making the economic and social case for MSP is the next step once an entry point is established. A good understanding of the economics underpinning the allocation of resources and space is a prerequisite for securing sustainable finance for MSP and its implementation. De-risking and leveraging sector-specific portfolios through integration is another powerful argument. Addressing issues and conflicts upstream of investments also makes the case, by giving investors some certainty that their projects won’t be delayed by environmental and social challenges. The social case for MSP usually focuses on effective and efficient delivery of public goods and services, most of which are ecosystem services or newly created jobs. Although making the case for an MSP investment in not typically part of a World Bank project, the Bank can help in this crucial task by providing analytical and advisory services, or external funding from sources such as the Global Environment Facility. Establishing enabling conditions may provide the first major opportunity for the World Bank to support and invest in MSP. The Bank’s extensive experience in investment and institution strengthening can work well to help clients establish enabling conditions, particularly in legal, institutional, and financial capacities. By creating clear legal frameworks, this work builds certainty for investors who seek predictable decision making. It is important also to have a single agency in charge of MSP, equipped with a clear mandate for overall coordination, management, implementation, compliance, and monitoring. The Bank has a range of tools that can support establishment of these and other enabling conditions, such as investment project financing and development policy operations. Formulating a marine spatial plan is a critical step for the development of a future investment portfolio for the World Bank. Planning identifies public and private sector investment opportunities across existing and emerging sectors by allocating marine space and establishing rules for sectors to operate within it. Experience of the past ten years-plus suggests that MSP success depends on a consultative process that engages all stakeholders, including marginalized and vulnerable communities at national and local levels. This dialogue should cover areas of use and address conflicts between users, including conservation. It can also explore climate change needs and social goals such as gender and transparency. A good plan will integrate sectors and find the right balance among existing and future uses. This may require innovative approaches such as co-location of uses, which in turn can attract investments that might otherwise be missing. The World Bank’s capacities in providing institutional strengthening, convening, and technical assistance can help produce a well formulated plan that all stakeholders support. As author Stephen Keague notes, “Proper planning and preparation prevents poor performance.” Implementation is the step where the investment portfolio envisioned in the plan is realized. Transformational change such as establishing specific use areas takes effect at this stage. Yet despite the enormous potential benefits, the number of plans that are actually implemented is quite low compared to the number of plans that are devised. Many factors, including financing shortfalls, constrain implementation. But one of the most important is lack of attention during plan formulation to the challenges that will come with implementation. These issues must be considered in detail beforehand. Plan implementation is often more effective when it has a schedule that is aligned with specific sector needs and guides stakeholders and investors. The Bank has a key role to play in making sure that planned investments go forward. It can help by providing access to its range of financing options for activities and investments, by helping to mobilize other public and private sources of finance, and by offering technical advice. This document, Volume 1, focuses on the MSP process. Important considerations that arise when sectors interact with each other are examined in Volume 2: Integrating Cross-Cutting Themes into Marine Spatial Planning. They include monitoring and evaluation of project progress and data, tools to better inform MSP, stakeholder engagement, gender biodiversity, and climate change. Giving these proper attention will help ensure that the World Bank’s safeguards are met and that MSP projects contribute to reaching Bank goals.