Condensation heat transfer of sonic steam jet in subcooled water was investigated experimentally over a wide range of steam mass flux and water temperature. Four different steam plume shapes were observed in present test conditions, and condensation regime map was given based on steam mass flux and water temperature. Maximum expansion ratio and dimensionless penetration length of the steam jet were also obtained in the ranges of 1.04-2.20 and 2.86-14.60, respectively. Then the semi-empirical correlations were given to predict the expansion ratio and penetration length, the results showed good agreement between the predictions and experiments. Moreover, temperature fields in the steam plume and surrounding water were measured. Axial temperature distributions represented the four typical steam plumes, and variation of the axial temperature confirmed existence of expansion and compression waves. Finally, surface renewal model was adopted to predict condensation heat transfer coefficients, which were in the range of 0.98-1.45 MW/m(2) K and mainly dependent on the physical property and steam plume shape, including expansion angle, expansion ratio and penetration length. (C) 2009 Elsevier Ltd. All rights reserved.