Coastal and inland water management are essential for protecting ecosystems, supporting human livelihoods, and ensuring economic stability in the face of climate change. Coastal management safeguards vital ecosystems, communities, and economies from erosion, flooding, and sea-level rise, while inland water management secures drinking water supply, sanitation, agriculture, and hydropower, directly impacting public health and productivity worldwide. Using Earth observation data from missions including CHIME, LSTM, ROSE-L, and CRISTAL, experts monitor coastal dynamics, hydrological processes, water quality, eutrophication levels, pollution, and habitat changes. These capabilities enable the detection of risks such as algal blooms, inform shoreline protection strategies, support sustainable fisheries, and guide resilient infrastructure and water resource policies, ensuring long-term environmental sustainability.