The COVID-19 pandemic has underscored the challenges in accessing healthcare services for foreign residents in Japan. However, a comprehensive understanding of these obstacles remains limited due to a scarcity of publicly accessible, government-led survey data. To bridge this knowledge gap, this study uses individual data from a 2020 comprehensive survey of foreigners in Japan, which was publicly released by the Center for Social Research and Data Archives, Institute of Social Science, The University of Tokyo. Using binomial logistic regression analysis, we identify the key demographics of those who face significant barriers to healthcare, including Thai nationals, part-time workers, those living in shared accommodations, individuals residing in the Chubu region of Japan, holders of designated activities visas, or those who are ineligible for healthcare insurance. In addition, we speculate that international students who do not reside in student dormitories may be another group facing difficulties in accessing medical services. Our study further suggests that aside from economic considerations, a limited understanding of the Japanese insurance system may be a primary factor behind some foreign residents' loss of insurance eligibility. We propose measures to alleviate these barriers, including directing resources that enhance healthcare accessibility toward areas with lower healthcare resource density, encouraging foreign residents' active participation in local neighborhood associations, enhancing the dissemination of basic information about Japanese health insurance, and advocating for the use of simplified language by medical institutions when interacting with foreign patients. The implementation of these measures could potentially enhance healthcare accessibility for foreign residents and facilitate their integration into Japanese society.