Supplementary data for the paper: "Investigation of Polyurethane-shelled Microcapsules for Self-Sealing Concrete Applications Exposed to Aggressive Environments"Open data concerning experimental work. This study evaluates polyurethane-shelled microcapsules containing a commercial water-repellent agent (WRA) as an autonomous self-sealing system for concrete in aggressive environments. Microcapsules (MIC) were synthesised via membrane emulsification and interfacial polymerisation, yielding a D50 of 77 µm and sufficient integrity for concrete incorporation. An optimisation study identified 2 by weight of cement (bwoc) % as the optimal dosage, balancing hydrophobic performance and mechanical properties. Cracked (100 and 300 µm) and uncracked specimens were exposed to freeze–thaw cycles with de-icing salts (FT), artificial seawater (MAR), and a chloride-rich solution (Cl). They were compared to the reference (REF) concrete.