In this article, I discuss how Taiwanese veterans and their mainland Chinese wives use transnational marriages as a strategy to obtain care and security in old age. The state's population, welfare and immigration policies shape the veterans' care needs and rights. Middle-aged mainland Chinese women choose to migrate to provide security for themselves and better educational and economic opportunities for their children. I use Stafford's concept of 'cycles of yang' to explain why, despite state provision of care, family members prefer reciprocity of care and why they choose transnational marriage in preference to other forms of family formation. This framework blurs the distinction between caregivers and care receivers, and conceptualizes differential care needs as part of the life course. I use the concept of a care diamond to analyse how state policies, communal care and market forces together shape care relationships in transnational families and patterns of transnational mobility.