The document summarizes the objectives and activities of the MCH-MSP INTERREG project, which aims to safeguard underwater cultural heritage by including it in maritime spatial planning in the Baltic Sea region. The project has 6 work packages related to mapping maritime cultural heritage sites, cross-sectoral planning, stakeholder engagement, and developing management solutions. It will conduct case studies in the Schlei region of Germany and Fehmarn to test pilot planning and management approaches. The overall goal is to share experiences, compare perspectives, and deliver tools and instruments to integrate underwater cultural heritage protection into maritime spatial planning and other sectoral plans.