Within the neocolonial context of ‘Plan Colombia’ in the early 2000s, agents of the US Federal Bureau of Prisons (BOP) took up position in the heart of the Colombian penitentiary administration to lead a reform based on the United States’ ultra-punitive penal regime. This paper analyses how the reform was set up on the ground, shedding light on the partially divergent expectations of the two governments. Drawing on recent literature on the mobility of policies and built forms, the paper argues that the introduction of US-inspired prisons in Colombia is a striking case where a mobile policy and a travelling architectural type coincided and complemented each other.