A study of decision making about birth registration in Indonesian families involved in transnational migration showed strong links between high migration and low birth registration for children of migrants, with negative implications for child statelessness and access to critical social services. The study included 42 individual interviews and seven focus group discussions involving 56 rural youth, parents, and grandparents in the high-migration district of East Lombok, Nusa Tenggara Barat province. Findings highlight the many ways that labour migration affects decisions about birth registration, citizenship, and family belonging for children. These insights expand our understanding of birth registration beyond the usual perspectives of governments, migrant advocates, and service agencies to include the cultural, social and familial experiences and decisions around the birth registration process.