Densities and heat capacities of dilute aqueous solutions (0,025 to 0,4 mol.kg-1) of trifluoromethane sulfonic acid (triflic acid) were measured with original high temperature / high pressure instruments at temperatures and pressures up to 574 K and 31 MPa, respectively. Standard molar volumes and standard molar heat capacities were obtained via extrapolation of the apparent molar properties to infinite dilution. The evolution of these standard derivative properties of the triflic acid with temperature and pressure is qualitatively compared with that of other acids of different strengths.