Prior research on interpersonal distance (IPD) has predominantly concentrated on specific nationalities or population groups within their respective regions. There is a dearth of studies investigating IPD differences among individuals of distinct nationalities coexisting in the same geographical location. This study aimed to examine the variances in IPD between 100 young Taiwanese participants (comprising 50 males and 50 females) and 100 Southeast Asian individuals (including 50 males and 50 females). This study also considered factors affecting IPD, including target genders and mask-wearing conditions. The results of the four-way ANOVA indicate that target gender and mask-wearing conditions had a significant impact on IPD (p < 0.001). While there were no significant main effects for region and participant gender, there was a noteworthy interactive effect between these two variables on IPD. In general, Southeast Asian participants exhibited lower sensitivity to changes in IPD in response to the independent variables in comparison to their Taiwanese counterparts; in certain instances, their IPD did not notably increase when confronted with targets not wearing masks. While prior research typically indicated that women tend to maintain larger IPD than men, the current study observed this gender difference only among young Taiwanese participants. However, such a gender gap was absent among young individuals from Southeast Asia.