arXiv:2611.06145v1 Announce Type: new Abstract: This study estimates the simultaneous charging factor (SCF) of electric vehicles (EVs) in Phu Quoc City, Vietnam, using a Monte Carlo simulation. Three planning scenarios (2030, 2035, and 2040) are developed from population-based EV uptake assumptions and vehicle-specific charging probability profiles over 24 hours, reflecting distinct operating patterns of motorbikes, cars, taxis, and buses. For each vehicle class and scenario, 1,000 simulation runs are performed to compute SCF and its uncertainty, reported via 95% confidence intervals. Results indicate that SCF decreases as EV penetration increases, implying more temporally dispersed charging demand and a reduced likelihood of extreme coincidence. For electric buses, SCF declines from 0.76 (2030) to 0.59 (2040), and other vehicle groups show similarly decreasing trends across the horizon. These SCF estimates provide practical inputs for grid-aware charging infrastructure planning, including diversity factors for sizing distribution transformers and feeders, identifying peak-hour stress, and informing demand management measures such as time of use tariffs and basic smart charging controls.