Tailings, like natural clayey soils, are prone to unsaturated behavioural changes as a result of changes in water content and suction. The equilibrium relationship between the moisture content and suction for soil, also known as soil water characteristic curve (SWCC), is commonly obtained in the laboratory using pressure plate equipment. This paper presents results of the laboratory determination of SWCC of four mine tailings and applies the van Genuchten curve fitting equation to estimate their air-entry values. High air-entry values were obtained for two tailings types and low values of the other two. The curves also show that the residual water contents of these tailings correspond to a value of suction of approximately 1000 kPa.