This paper summarizes the study design of the Rural–Urban Migration in China and Indonesia (RUMiCI) project. We first discuss the overall distribution of migrants in Indonesia and the selection of survey cities. Next, we describe the process of identifying the migration status of each household in the sampling frame, using a presurvey listing. This is followed by a discussion of the sampling method, focusing on the oversampling of migrant households. The timeline of the survey is then discussed and the questionnaire is summarized. Finally, we provide some concluding remarks.