This work reports experimental data of the speed of sound in liquid trifluoromethane (HFC23, or R23) from T = (258 to 303) K at pressures up to 65 MPa, measured with a pulse-echo method adapted from Papadakis((1)) and Guedes et al.((2)) The results are fitted to a rational approximant and compared with literature data.((3)) Derived thermodynamic properties such as the isentropic compressibility kappa(s), the isothermal compressibility kappa(T), the cubic expansion coefficient alpha(p), and the specific heat capacity at constant pressure c(p) are calculated by combining the present experimental data with the density values published by other authors.((4-11)) The estimated properties are compared, where possible, with literature data.