Along with the rapid urbanization process in Beijing, China, the number of older rural-urban migrants is increasing. This study aims to understand how Chinese rural-urban migration in older age is influenced by, and impacts on the migrants’ mobilities. This study draws on a new conceptual framework of mobile vulnerability, influenced by physical, economic, institutional, social and cultural mobility, to understand older people’ experiences of migration from rural to urban areas. Forty-five structured in-depth interviews with older rural-urban migrants aged 55 and over were undertaken in four study sites in Beijing, using the constant comparative method. Results demonstrate that rural household registration (hukou) is an important factor that restricts rural older migrants’ institutional mobility. As older migrants’ physical mobility declines, their mobile vulnerability increases. Economic mobility is the key factor that influences their intention to stay in Beijing. Older migrants also described coping strategies to improve their socio-cultural mobility post-migration. These findings will inform service planning for older rural-urban migrants aimed at maintaining their health and wellbeing.