This article presents research into surface coatings produced by the electro-spark deposition (ESD) method on aluminium using a copper electrode. ESD is a surface modification technique that uses short current pulses (electrical discharges) to transfer material from the working electrode (anode) to the workpiece (cathode). The evaluation involved observing the effect of voltage and capacitor capacitance during the ESD process on the thickness of the ESD coating. To minimise the number of experiments required, a two-factor, five-level Hartley experimental design was selected. The study demonstrates the potential use of computed tomography to monitor the condition of the resulting ESD coating. Unlike previous studies, where the evaluation of ESD coatings was mainly based on the analysis of single metallographic cross-sections, in this work computed tomography was used for three-dimensional, non-destructive evaluation of the coating continuity and geometry, as well as quantitative analysis of its thickness. VG Studio software enables visualisation of the resulting ESD coating, including measurement of its thickness or volume. Microscopic observations were then carried out on the prepared samples to analyse the thickness and structure of the coatings. The use of tomographic studies in the analysis of ESD coatings ensures significantly greater representativeness of the results compared to traditional microscopy. It allows for a spatial assessment of the coating’s continuity, which eliminates the risk of misinterpreting quality based on individual cross-sections. Furthermore, the spatial data obtained form the basis for precise mathematical models, enabling a better understanding of the process’s energy balance and more accurate prediction of ESD coating thickness as a function of process parameters. The scientific novelty of this work is the three-dimensional analysis of the obtained coatings using the ESD method, as opposed to the previously performed analyses of metallographic cross-sections.