This study examined the development of intercultural sensitivity among college students in Japan, focusing on the differences between the impacts of domestic and overseas English language programs. Previous research has focused primarily on students with highly international orientations; however, this study examined students with low international orientation who participated in intercultural programs. The purpose of this study is to explore effective pedagogical approaches to promoting intercultural understanding and enhancing English language learning. The participants were divided into two groups: one that participated in a two-day residential English immersion program at British Hills in Japan, and another that participated in a two-week short-term study abroad program at Holmesglen Institute of TAFE in Australia. The Intercultural Development Inventory (IDI), based on Bennett’s (1986) Developmental Model of Intercultural Sensitivity (DMIS), was used to measure changes in intercultural sensitivity before and after program participation. The results indicated that both programs contributed to increases in intercultural sensitivity, however, students in the Holmesglen program demonstrated more significant changes, particularly in the later stages of the DMIS model, such as “Acceptance of Difference” and “Adaptation to Difference.” The results of the study suggest that more extensive and immersive intercultural experiences, such as study abroad programs, are more effective in fostering deep intercultural understanding and enhanced adaptability. The study emphasizes that spending more time in intercultural environments is important for developing intercultural competence. While short-term domestic programs provide valuable introductory experiences, they may not be sufficient to achieve advanced intercultural adaptation and integration. The findings underscore the need for practical, immersive experiences to cultivate meaningful growth in intercultural sensitivity among students. Future research should explore the potential of long-term programs to enhance intercultural competence.