Blue Carbon Ecosystems (BCEs) such as mangroves, seagrasses, and tidal salt marshes are vital natural carbon sinks with exceptional climate mitigation potential. They sequester and store carbon more efficiently than terrestrial forests while supporting biodiversity, livelihoods, and coastal protection. Yet, these ecosystems face accelerating degradation from human and climatic pressures. This chapter reviews their global distribution, carbon storage capacities, and ecosystem services. It also examines conservation initiatives across nations and the donor–receiver framework of blue carbon wealth. The integration of geospatial technologies, remote sensing, GIS, and machine learning, enhances BCE monitoring and management. Strengthened policies, financing mechanisms, and international cooperation are essential to safeguard BCEs and sustain their role in achieving global climate goals.