Background: The rapid increase of Indonesian migrants to Thailand in the last two decades due to greater regional integration, transport connectivity, and internationalization of education. Different religion, socio-culture, and other sociodemographic factors might affect their adaptation to the Thai society.

Method: A mixed-method design was employed for data collection. The quantitative data were derived from an online survey of 268 respondents, while the qualitative data came from literature review, in-depth interviews, focus group discussion, and direct observation.

Results: Indonesian migrants tended to opt for an integration strategy and to a lesser extent a separation strategy, with assimilation and marginalization ranking lowest in the acculturation scale. Association test of socio-economic characteristics and acculturation strategies further showed conforming results with minimum variation. Qualitative findings broadly confirmed the overall preference for integration as the majority of Indonesian migrants, composed of students and professionals, is well-adapted to Thai society, despite religion and language differences. A minority composed of Indonesian housewives were more inclined toward separation when not engaged in entrepreneurial activities. Not surprisingly, the small number of Indonesian women in mixed marriages with a Thai national living in relatively isolated rural areas were more assimilated in Thai society. A counterintuitive association of assimilation and marginalization was further noted, which requires further research for a more complete explanation.

Conclusion: The dominant acculturation strategy of Indonesian migrants in Thailand is integration, followed by separation. Several sociodemographic factors, including education and occupation, influence these strategies.

Keywords: acculturation strategy; Indonesian migrants in Thailand; migration