The new RSS SMAP Version 4.0 data spans the full mission, from 2 April 2015 to the present. Enhancement with this version include: 1) an improved land correction allowing retrievals closer to the coast (30-40km), 2) implementation of an improved sea-ice mask based on AMSR2, revised solar flagging, and inclusion of SSS uncertainty fields in the Level 3 (L3) products. Global coverage L3 data products include an 8-day running mean as well as monthly averages. Level 2 swath data are also available as part of the product release. They are available with a latency of 3 days for the Level 2 dataset, and 8 days and 1 month for the respective L3 products. The spatial resolution of the SMAP sensor and improved land correction with this V4.0 release allows for improved applications to coastal and regional studies. The image shows global maps of SSS (left panel) and associated uncertainties (right) on 27 March 2015 from the V4.0 L3 8-day running mean product.