Primary care is vital for disease prevention, but factors influencing access to primary care physicians (PCPs) in Japan are not well understood. Using data from 28,481 respondents in the 2023 JACSIS survey, we analyzed demographic, health, and community characteristics associated with having a PCP. The proportion of individuals with a PCP was lowest in the early thirties and increased with age. Employment demands, child-rearing responsibilities, living alone, and weak community ties were Primary care is vital for disease prevention, but factors influencing access to primary care physicians (PCPs) in Japan are not well understood. Using data from 28,481 respondents in the 2023 JACSIS survey, we analyzed demographic, health, and community characteristics associated with having a PCP. The proportion of individuals with a PCP was lowest in the early thirties and increased with age. Employment demands, child-rearing responsibilities, living alone, and weak community ties were associated with a lower likelihood of having a PCP, while older age, chronic conditions, health-conscious behaviors, and strong community relationships increased PCP access. Mental health issues and a history of drug use were associated with lower PCP proportions. Our findings suggest that improving PCP access in vulnerable groups requires attention to health literacy, time availability, and community support, rather than focusing solely on income or education. Targeted efforts may help increase PCP utilization among those most in need.associated with lower likelihood of having a PCP, while older age, chronic conditions, health-conscious behaviors, and strong community relationships increased PCP access. Mental health issues and a history of drug use were associated with lower PCP proportions. Our findings suggest that improving PCP access in vulnerable groups requires attention to health literacy, time availability, and community support, rather than focusing solely on income or education. Targeted efforts may help increase PCP utilization among those most in need.