The simulation of seismic wave propagation generally requires dealing with complex tridimensional geometries that are irregular in shape and have non‐uniform properties, features that make the application of the generalized finite difference method in this field interesting. This work continues the extensive developments by the research team focused on the simulation of seismic wave propagation in two‐dimensional domains. In this new contribution, the general formulation and the treatment of free surface boundary conditions are extended for the three‐dimensional case, and the results obtained from different examples are analyzed.