The program Saltywatr1.0.0 is collection of Matlab routines that implement a numerical solution of the shallow-water flow equations for rivers, estuaries, and the coastal sea. Imagine a two-dimensional planar flow, as in a shallow estuary, with spatial variations in velocity, water height, and salt. The model calculates the above flow variables using the conservation equations for water, salt, and momentum. To simulate flow driven by differ- ences in salt concentration, the momentum equation is coupled to the conservation of salt through the hydrostatic pressure term. Saltywatr is capable of modeling domains of irreg- ular geometry, such as estuaries and rivers.