This data set contains research data related to the article "In situ X-ray CT imaging of transient water retention experiments with cyclic drainage and imbibition" to be published in the Journal Open Geomechanics. The research data include 3D CT images acquired during cyclic drainage and imbibition of a sand specimen in a transient in situ water retention experiment that was run in the X-ray tomograph at Laboratoire 3SR at Univ. Grenoble Alpes. Besides the CT images, also data from the multiphase image analysis as well as macroscopic water retention data, measured in parallel to the CT scans, are published.