This qualitative research aimed to study the social interactions of Japanese elderly staying long-term in Chiang Mai. The key informants were nine Japanese, 60 years of age and up, staying for long-term in Chiang Mai, selected by purposive sampling. The informants holding Non-Immigration Visa, code O-A (long-stay), and staying in Chiang Mai for more than five years provided clear information on the studied issues. Data were collected by conducting in-depth interviews and using triangulation data testing and analyzed by using content analysis and theme analysis for summarizing the research results. The results found that the Japanese elderly regularly interacted with people in the community via daily life and social activities in daily face-to-face conversation. The Thai language was used in communications with community members. The interactions’ scope, frequency, and intensity were in the neighborhood. The key informants spent time building familiarity with people and limited special physical areas with the capacity to create social interactions. Long-term residence in Chiang Mai for more than three years was found to have caused elderly Japanese informants to have interactions with the environment while connecting the micro-system, the mesosystem, the exo-system, and the macro-system, causing elderly Japanese informants to have broad social networks, resulting in good learning and understanding of community cultures, laws, rules, norms and values in addition to enabling behaviors consistent with community culture, creating understanding and respect for cultural differences and ability to live in harmony in Thai society.