Delamination onset of composite laminates is investigated under cyclic loading by numerical simulation and fatigue experiments. Firstly, laminated composites in the form of double cantilever beam (DCB) testing specimens are fabricated. Two different manufacturing methods including hand layup and vacuum infusion process are used for fabricated three different lay-up configurations. All specimens are subjected to cyclic loading under displacement control conditions. The variations of compliance versus number of cycles are monitored and recorded during the performed fatigue tests. Then, the developed novel approach in the companion article (Part I) is implemented in this article and numerical simulation is performed to predict the onset of fatigue-induced delamination for the same investigated testing specimens. Results show a good agreement with experimental data. It is observed that the proposed model is able to capture the interfacial degradation by employing a damage evolution law in the onset stage of delamination.