Marine planning in England aims to balance competing uses of marine space and resources through a process established by the Marine and Coastal Access Act 2009. The legislation requires marine plans that translate high-level national policies into spatial guidance for regional plan areas. The first plans are being developed for the East marine plan areas through stakeholder engagement, evidence gathering, and defining key issues to guide sustainable decisions about marine activities. Challenges include the complexity of planning at a large scale across environmental, economic, and social factors while balancing competing interests. Lessons indicate the need for political commitment, dedicated resources, and flexibility in the long-term planning process.