These are the datasets analysed in the publication "Dynamics of Water Absorption in Callovo-Oxfordian Claystone Revealed With Multimodal X-Ray and Neutron Tomography" by Stavropoulou et al. in 2020 in Frontiers in Earth Science, DOI: https://doi.org/10.3389/feart.2020.00006 File 1 contains the 3D reconstructed x-ray and neutron tomography volumes analysed in the paper. State 002 is taken as a reference and the greylevels of all images in the times series for both x-ray and neutrons are rescaled using two characteristic image features (top-cap and air in the case of x-rays) linearly to align with 002. Neutron volumes are rescaled to the same pixel size as 2-bin x-ray volumes, and a mean registration is applied to align neutrons with x-rays. Furthermore, a bilateral filter is applied to the neutron tomographies (domain sigma = 1, range sigma=3000). Full scale images are available at https://doi.ill.fr/10.5291/ILL-DATA.UGA-42 File 2 contains the joint histograms for registered pairs of images, as visible in Figure 4 and Figure 5. File 3 contains the results of the digital volume correlation performed with the spam tookit. The overall "registration" is used to create Figure 6 The global correlations available in "gdic" are used to create Figures 7, 8 and 9.