Migration induces social change across the Indonesian archipelago as shifts in demography reshape communities. The process of migration not only transforms host communities, but also the migrants involved. Drawn from ethnographic research, this qualitative study examines migration's influence in shaping Muslim migrant religion in Sumba and West Timor, East Nusa Tenggara Province, Indonesia. Data was collected through semi-structured interviews of 108 migrants between February 2018 and February 2019. Research sites include Waikabubak and Anakalang on Sumba Island and Kupang, Baun, and Oe'Ekam on Timor Island. To analyze Muslim migrants' experience, the study utilizes a five-pillared ethnographic framework. The pillars for this framework are: (1) motivations for migration, (2) adaptations of migrants, (3) changes to migrants' religious belief and/or practice, (4) migrant institutions, and (5) migrant perceptions of the Christian majority. The vast majority of participants to this study began their migration due to economic and employment concerns, few having religious motivations for their relocation. At the personal level, this offers little credence to host community concerns of motives of Islamization. Migrants' religiosity and religious communities, further, play little role in the initial stages of migration as migrants rarely seek spiritual advice and support concerning their move. Migration from Muslim-majority regions of Indonesia to Christian-majority East Nusa Tenggara disrupts the religious and cultural patterns of migrants which leads to social and religious adaptations after arrival. Migrants mitigate the loss of ethnic and religious bonds through changes in personal habits, participation in religious communities, and through ethnic enclaving. The experience of migration proves to be a "theologizing experience" as a majority of participants reported that their experience as migrants produced positive changes in their personal religious belief. The increased intensity of religious belief draws from processes of individualization, perceived increases in personal liberty, and higher levels of social coherence due to both intrareligious and inter-religious diversity in the host context. While the transformations of the migrants' individual expressions of Islam are numerous, the intrareligious and inter-religious diversity has a liberalizing effect on migrant perspectives of religious others. The experience of these migrants as religious minorities is positive, with participants finding their contexts to be more tolerant than their respective sending societies.
Key Words: Muslim migration, religion, Indonesia, social change