Presented at the 2018 Ocean Salinity Science Team and Salinity Continuity Processing MeetingVariations of sea surface salinity (SSS) in the southeast Asian Seas (SEAS) have important implications to ocean circulation and climate variability. Systematic monitoring of salinity changes in the SEAS region has been extremely challenging due to the complicated geometry and other factors. This has hindered our understanding of freshwater changes in the SEAS region, the relationships with climate variability (e.g., monsoon, El Niño-Southern Oscillation, and Indian Ocean Dipole), and the potential implications to climate predictions. NASA's Soil Moisture Active Passive (SMAP) satellite has been providing sea surface salinity (SSS) measurements at 40-km spatial resolution and 8-day repeat cycle since April 2015. Here we examine seasonal-to-interannual variations of SSS in the SEAS region using SMAP SSS in relation to other satellite observations, including precipitation, sea surface height, ocean surface currents, ocean color, and soil moisture. The analysis results illustrated the relationships of SSS variations with monsoonal forcing in the northern and southern parts of the SEAS region, the effects of the 2015 positive Indian Ocean Dipole, the 2015-16 El Niño, and the exchange between the SEAS and the Pacific Ocean.