Located in the south of Brazil, the Patos Lagoon is the world’s largest choked lagoon. The extensive mud deposits that surround its estuary indicate a substantial transport of suspended matter to the continental shelf by its plume. This study aims to develop a regional algorithm for estimating the total suspended matter of the Patos Lagoon coastal plume using remote sensing data combined with oceanographic measurements. We develop a polynomial correlating total suspended matter with the reflectance of the 667-nm-centered band of the Moderate-Resolution Imaging Spectroradiometer (MODIS), aboard the Aqua satellite. We use the satellite-based estimates to investigate the development and fate of the plume and to quantify the exchange processes between the estuary and the coastal zone. The seasonal averaged total amount of suspend matter exported by the plume ranged between values in the order of 106 and 107 ton. The plume shows a residual displacement to the south of the estuary mouth, though it can be transiently displaced northwards under the influence of strong southerly winds. The river discharge determines the plume’s suspended matter transport, whereas the wind shapes its form and determines its spreading. The plume’s variability shows well-marked cycles with semi-annual and quasi-annual frequencies, which could be identified by EOF and wavelet analyses.