Measurements of diffusion from slug releases of fluorescent dye performed in the bays of Texas are compiled along with attendant hydrographic and hydrometeorological data. These data sets are confined to conditions of low surface wave activity to better expose the effects of local currents on diffusion. Development of a dye patch is parameterized in terms of a lateral diffusivity, which measures ''turbulent'' diffusion, and a longitudinal dispersion, which measures the effect of vertical shear in the current. The former is found to follow a local 4/3-power dependence upon scale and has a noisy correlation with current speed. The latter is found to be consistent with a theortical model predicting a variation with the square of current speed and inverse variation with the squared Ch¿zy coefficient. These data are considered to be generally representative of the shallow lagoon environment typical of Gulf of Mexico bays.