New features have been added and several necessary changes have been made to the standard WAM-cycle4 (WAMC4) model code for it to run efficiently when applied to shallow water regions. The restriction of having a source term integration time step smaller than or equal to the propagation time step was relaxed, considerably reducing the computational time needed. An additional reduction in computing time and an increase in accuracy were obtained by introducing a split-frequency time step. There is now a choice of using the octant or quadrant coordinate system for the propagation of the wave energy. The source term integration and, more particularly, the use of a limiter on the energy growth, were studied. For the evaluation of the energy decay in shallow water areas, different bottom friction formulations and an expression for the energy dissipation due to depth-induced wave breaking were added to the code. The procedure to make nested runs was changed in order to save data storage space and time spent on input/output (I/O) operations. Several other changes were done in order to improve the accuracy in high-resolution applications. A number of simple or idealised example applications are included to illustrate some of these enhancements.