Anzali Wetland is one of the most important aquatic ecosystems in northern Iran and has experienced marked hydrological fluctuations in recent years under climatic variability and human pressures. This study aimed to assess multi-sensor changes in water level and surface water extent using observations from different remote sensing missions. Sentinel-3 radar altimetry data for 2016–2025 and Landsat-8 imagery for 2016–2024 were processed. Surface water was extracted using the NDWI and MNDWI indices, while corrected radar altimetry observations were used to analyze water-level variations. Cumulative distribution, dry–normal–wet classification, coefficient of variation, and extreme-event analyses were also performed. The results showed substantial water-level variability and pronounced changes in surface water extent. During relatively wet periods, the inundated area exceeded 60 km², whereas during critical low-water periods it declined to less than 10 km². More than half of the observations had a surface water area below 15 km², and the frequency of dry conditions increased after 2021. The integrated results indicate a shift toward lower and more unstable hydrological conditions. These findings highlight the need for integrated water-resource management, protection of inflows, restoration of hydrological connectivity, and continued satellite-based monitoring to support conservation and restoration of Anzali Wetland.