Comprehensive and accurate measurements of the speed of sound in pure ethane have been carried out in the liquid and supercritical regions by a double-path-length pulse-echo technique. The measured data cover the temperature range from 240 K to 420 K with pressures up to 100 MPa. The expanded measurement uncertainties at the 95% confidence level amount to 2.1 mK for temperature, 0.007% for pressure, and 0.01% for speed of sound with the exception of a few state points in the vicinity of the critical point, where the uncertainty increases up to 0.016%. The quality of the measurements is demonstrated by comparisons with literature data and the fundamental equation of state for ethane by D. Bucker and W. Wagner [J. Phys. Chem. Ref. Data 35 (2006) 205-266]. (C) 2015 Elsevier B.V. All rights reserved.