The process of Welsh devolution has marshalled major political, social and institutional change. While scholars within various disciplines have attempted to make sense of these changes, the discipline of criminology remains something of an exception. This article offers an examination of the unique Welsh criminal justice policy space that has been opened up by devolution in Wales. The article provides a long overdue assessment of how drug policy in Wales, while continuing to straddle the UK Government’s criminal justice responsibilities, is configured and shaped within post-devolution Wales. The empirical findings presented here reveal the existence of a distinct Welsh drug policy as well as discovering clear limitations to Welsh policy divergence. The article outlines the need for criminologists to take Wales – and the Welsh policy space – more seriously, while highlighting the need for criminologists to become more attuned to the considerable effects being made by constitutional change.