GNSS Interferometric Reflectometry (GNSS-IR) is an emerging ground-based remote sensing technique that uses the interference between direct and coherently reflected GNSS signals. This technique has been applied to measure a variety of variables including water level, significant wave height, snow accumulation, ice freeboard, permafrost melt, soil moisture, vegetation water content and coastal subsidence. As the community of GNSS-IR developers and users continues to grow, this session seeks to highlight advances in the (near real-time) acquisition, processing, analysis and application of GNSS-IR in environmental sensing. The session welcomes contributions on algorithmic and technical improvement of GNSS-IR models, as well as the development of open-source hardware and software. We also invite presentations on GNSS-IR data products and their validation, the optimal exploitation of geodetic and affordable GNSS sensors for GNSS-IR applications and initiatives for (near) real-time monitoring of environmental variables.