3D microstructure datasets for SrTiO3 polycrystal acquired by high energy x-ray diffraction microscopy (HEDM) at the Advanced Photon Source (APS) at beamline 1ID. The first dataset (t0) was collected after the microstructure was sintered (1425°C, 1hr, oxygen) and pre-annealed (1400°C, 10 hr, forming gas). The second dataset (t1) was collected after an additional annealing step at 1400°C for 70 hr under forming gas. The data is provided in a .dream3D file, which includes post-processing information completed in Dream3d and grain information (orientation, centroid, grain size) in voxel arrays. See Dream3D for more information about the file format and storage. For more details about the data cleanup and material processing, please see the papers listed below. V. Muralikrishnan, H. Liu, B. Conry, C.J. Marvel, M.P. Harmer, G.S. Rohrer, M.R. Tonks, R.M. Suter, C.E. Krill III, A.R. Krause, Observations of unexpected grain boundary migration in SrTiO3. Scripta Materialia. 2023; 222:115022. 10.1016/j.scriptamat.2022.115055. V. Muralikrishnan, Z. Xu, G.S. Rohrer, A.R. Krause, The effect of local geometry and relative energy on grain boundary area changes during grain growth in SrTiO3. Journal of the American Ceramic Society. 2025; 108[4]:e20319.