Ship wakes are waves that are generated by a passing vessel in the coastal and marine areas. In recent years, the operation of high-speed crafts (HSC) has caused major concerns on the impact of ship wakes to the coastal environment. Among the suspected problems are safety of visitors at the beach, wave disturbances at small jetties and coastal erosion. The objective of this paper is to describe the application of the slender body theory coupled with the MIKE 21 Boussinesq-type wave module to predict the propagation and transformation of ship wakes in the far field region. The internal boundary condition is generated using a program that calculates the moving transverse flux across a straight line which represents the trajectory of the ship. The numerical model has been validated with an extensive series of experimental data from physical model test, which have been used to establish the accuracy and area of application of the modelling approach. The results show that the model provides a good agreement with measurements for critical to super critical depth-Froude numbers. Hence, it is a useful tool for assessing the impact of ship wakes from HSC in shallow coastal waters.