Waste foundry sands are a byproduct of cast-metal processes. There is minimal geotechnical characterisation of these artificial soils in the literature, and as such their potential applications in construction have not been extensively explored. Due to the presence of coal and bentonite, their unsaturated properties, hydraulic behaviour, and mechanical response can be complex, and need to be better understood before assessing the feasibility for geotechnical applications. This study provides hydromechanical characterisation of a waste foundry sand in terms of soil-water retention, swelling, compression, and shear behaviour.