This article addresses the importance of understanding informal and customary arrangements to comprehend social security in the contemporary Indonesian context. Highlighting the work of K. von Benda-Beckmann, the focus is on how people foster circles of solidarity to deal with vulnerability, and needs for food, shelter and care, while creating their social security mixes, in which state provisions and community arrangements are combined. We argue that – since there is no welfare state capable of providing for all aspects of social security – people will depend on informal provisions that belong to the realm of moral economy. Based on both authors’ field research, the article explains how this social security mix functions in practice, with examples from the Indonesian islands of Bali and Sumba. We explore to what extent such a moral economy persists, and how moral economy arrangements for mutual support differ from state welfare, in particular from normative and relational perspectives, and how people shape articulations between the two support systems. We argue, in line with the von Benda-Beckmann approach, that it is crucial to understand social security practices as a mixture resulting from Indonesia’s economic and legal pluralism.