The NASA Soil Moisture Active Passive (SMAP) mission record of Earth observations now spans over six years. The mission continues to produce science data products based on global low-frequency microwave radiometry with science applications across Earth System science including: global and regional water, energy and carbon cycles, oceanography (including surface salinity, winds and ice coverage), and global ecology. The science data products complete global coverage in 2 to 3 days depending on latitude. The multi-year record allows insights into year-to-year and season-to-season differences in these Earth System scientific disciplines. The science data have also found new applications such as understanding water exchange in the soil-vegetation-atmosphere continuum and mapping melt and re-freeze processes over land ice masses. The science data products are also being used to test the fidelity of land-atmosphere coupling processes in numerical climate and weather models. Since soil moisture is a key determinant of rainfall-runoff processes and the bowen ratio, the SMAP data are being used in several applied science contexts such as flood forecasting and drought and heat-waves monitoring. This session includes presentations on the results of SMAP data use in hydrology, Earth system science and natural hazards applications.