Experimental densities for seven mixtures of water+1-butyl-3-methylimidazolium iodide, [C 4 mim][I], +1-hexyl-3-methylimidazolium chloride, [C 6 mim][Cl], +1-hexyl-3-methylimidazolium bromide, [C 6 mim][Br], +1-hexyl-3-methylimidazolium iodide, +[C 6 mim][I], 1-octyl-3-methylimidazolium chloride, [C 8 mim][Cl], +1-octyl-3-methylimidazolium bromide, [C 8 mim][Br] and +1-octyl-3-methylimidazolium iodide, [C 8 mim][I]) were measured across the composition at T=(298.15 and 308.15) K and atmospheric pressure. The excess molar volumes, V m E , were calculated and their compositional variation was mathematically represented by Redlich–Kister type equation. The partial excess molar volumes of water as well as the corresponding RTIL were calculated across the composition. The partial molar volumes at infinite dilution for the respective components and the corresponding standard transfer volumes for different combinations of water+RTIL mixtures were also calculated.