The Geostationary Littoral Imaging and Monitoring Radiometer (GLIMR) instrument is a hyperspectral ocean color sensor launching after 2026 that targets the Gulf of Mexico and other coastal and ocean waters of North and South America. With its vantage point from geostationary orbit, GLIMR will be the first hyperspectral ocean color sensor in the Western Hemisphere to study ocean processes at the diurnal timescales required to observe the dynamic ecological, biogeochemical and physical processes typical of coastal and ocean waters.