During transient intrusion of molten metal into water, metal go through cooling, breakup before fully solidified. This paper describes a numerical code which combines cooling, solidification and breakup in a single computation. In the code free surface of jet is tracked by Volume of Fluid Method (VOF), both the heat transfer and viscosity variation during liquid-solid phase change are taken into account. The simulation results of melt jet pattern, front position history, jet breakup length and breakup time are in good agreement with the experimental results. The effects of interfacial temperature and jet velocity are also determined. The molten jet thermal history and solidification, droplet generation rate at different penetration times, which are difficult to observe in experiment, are presented to gain an insight into this complicated process. Solidified metal proportion increases with jet penetration depth. Melt jet breakup with surface solidification can be divided into three zones in space: (1) liquid core, (2) solidifying zone, (3) solid droplets. These simulation data are helpful to substantiate the understanding of the phenomena during molten melt jet interactions with water. (C) 2017 Elsevier Ltd. All rights reserved.