The supporting data for C. Harris et al., 2021, 'The impact of heterogeneity on the capillary trapping of CO2 in the Captain Sandstone', International Journal of Greenhouse Gas Control. We supply experimental and numerical simulation data used in the paper. The supplied codes reproduce each figure. The codes are split into 2 folders, descriptions of each of the folders are given below: 0 - README. This contains detailed instructions on using the supplied files. 1 - Main simulations. This contains the code to produce the main CMG (Computer Modelling Group) simulations outlined in the paper, with various input variable files. 2 - Other figures. This contains the code to produce other figures within the paper which do not rely on numerical simulations, including the experimental data.