In the mid-20th Century, the practice of bartering was one of the most prevalent forms of economic transaction around the Indonesian Archipelago. The most prevalent and crucial for Indonesian society was the trade conducted along the border between Singapore and Sumatra. The government centred in Jakarta often approved and even encouraged barter with Singapore at the regional and national level. In many cases, however, bartering along the borders was done autonomously by the regional government and traders, and often out of state control. In these circumstances, the central government sometimes “illegalised” barter trade, while the regional government and societies, arguing that their barter transactions were “licit”, issued a challenge to the government’s order. Such tension and conflict over barter in the region was exacerbated by political upheavals such as regional rebellions in the 1950s and the Konfrontasi in the 1960s. This article traces changing policies and discourses regarding “barter” between Singapore and the Indonesian islands (mostly Sumatra) in the mid-20th Century, and highlight how an economic transaction was politicised, and how the ideas of licitness and legality were in confrontation in certain political backgrounds.