CoastSat is an open-source software toolkit written in Python that enables users to obtain time-series of shoreline position at any coastline worldwide from 30+ years (and growing) of publicly available satellite imagery. There are four main functionalities: assisted retrieval from Google Earth Engine of all available satellite images spanning the user-defined region of interest and time period automated extraction of shorelines from all the selected images using a sub-pixel resolution technique intersection of the 2D shorelines with user-defined shore-normal transect tidal correction