[19-May-2026] González-Gambau, V., García-Espriu, A., Gabarró, C., Sánchez-Urrea, M., González-Haro, C., López-López, A., Umbert, M., Hoareau, N., de Andrés, E., Turiel, A., and Olmedo, E. Monitoring freshwater fluxes in polar regions is essential for understanding how global warming affects sea-ice melt and influences global ocean circulation. These rapid environmental changes demand continuous monitoring; however, the extreme conditions in polar regions make sustained in situ observations particularly challenging. In this context, L-band satellite observations provide a unique capability for continuous monitoring of sea surface salinity (SSS). Although the sensitivity of L-band brightness temperatures (TB) to salinity decreases in cold waters, significant efforts within the L-band remote sensing community have led to the development of advanced retrieval algorithms capable of providing increasingly accurate SSS estimates in polar regions. Here, we present a summary of the work carried out at Barcelona Expert Center for the development of two new SSS products: Arctic+ Salinity v4 (García-Espriu et al., 2026) and SO-FRESH, focused on the Southern Ocean (González-Gambau et al., 2025).