A new integrated concentrator photovoltaic (CPV) system using phase change material (PCM), and a water jacket is developed to increase the thermal regulation period during the daytime and enhance heat removal from the liquid PCM during the nighttime. The system integrates a CPV cell with three different designs of the PCM heat sink: a single-cavity, a three-parallel cavity, and five-parallel cavity configurations. To evaluate the electrical and thermal performance of the integrated CPV-PCM-water jacket system, a comprehensive 2-D mathematical model for CPV layers combined with PCM, and water jacket flow is developed. The full model couples’ thermal models for CPV layers and thermo-fluid models that consider the phase-change phenomenon and water jacket flow. Numerical simulation of the comprehensive model is performed to estimate the transient temperature variation of the employed PCM during melting and solidification processes along with the local and average temperatures of the silicon solar cell. Results reveal that the integrated CPV-PCM-water jacket system attains a significant reduction in the average solar cell temperature throughout the daytime. By using a single cavity configuration at a concentration ratio (CR) of 20, a noticeable decrease in solar cell temperature of around 124 °C is achieved in comparison to the conventional CPV-PCM system. Moreover, at the end of the nighttime, about 55% of the liquid phase changed to solid phase, compared to the conventional CPV-PCM system, where about 10% of the liquid phase transformed to solid phase. By using a five-cavity configuration, the solar cell temperature is maintained below 72 °C during the full day and the average electrical efficiency throughout the daytime is about 17.7%. Furthermore, the liquid phase has completely transformed to solid phase at the beginning of a new cycle of insolation. The present findings can open doors for further research into merging the advantages of passive and active thermal regulation for CPV systems.