These data comprise laboratory observations of oscillatory flows over mobile sand ripples. The data were collected January 6-7, 2016, in the small-oscillatory flow tunnel (S-OFT) in the Sediment Dynamics Laboratory at the U.S. Naval Research Laboratory (NRL), Stennis Space Center, Mississippi (MS), while Donya Frank-Gilchrist was a National Research Council post-doctoral fellow there. The flow tunnel has a 2-m long acrylic test section which was filled with coarse quartz sand. A piston and flywheel were used to drive the oscillatory flows, from which equilibrium sand ripples developed. The experimental setup comprised of three Photron cameras and a double-pulsed Litron Nd:YAG laser, synced and sampled at 100 hertz (Hz) in double-framed mode. The fluid velocities were obtained through Particle Image Velocimetry (PIV) processed with LaVision DaVis 11 software. The images were also rectified and exported from the original file format (.im7) to a non-proprietary format (Tagged Image File Format, .tif) for inclusion in this data release. For further information regarding experimental setup, methods, and results, refer to Frank-Gilchrist and others (2018, 2024).