A Gust erosion chamber was used to apply horizontal shear stress to sediment cores obtained from San Pablo and Grizzly (within Suisun) Bays in California. A pair of sediment cores were collected from the same approximate locations in each bay five times between January 22nd, 2020 and March 11th, 2020 for a total of 10 experiments and 20 sediment core results. Locations were chosen to capture the benthic variability along the estuarine salinity gradient, are established benthic monitoring stations, proximity to historic/restored wetlands, and practicality for field operations. Sampling dates targeted spring and neap tide conditions. An onshore experiment was conducted on each core to apply shear stresses with stepwise and monotonic increases. Effluent following erosion was monitored for turbidity and sampled for suspended-sediment concentration analysis. For each core, experiment results were used to calculate the following at each applied shear stress step of the experiment: 1) critical shear stress required to initiate erosion, 2) mass eroded per square meter, and 3) the erosion rate coefficient (M). Equations used for calculations are outlined in Process Step 3 of this data release.