Internationally, there is a current rising demand for police to participate in complex peace operations. Achieving multilateral â€˜integrated missionsâ€™ has become a key objective for these operations. One of the key requirements for such operations is interoperability between police drawn from different countries. Australia has had police serve in multilateral and other kinds of missions in Timor-Leste since 1999. In this article, we draw on interviews with 64 Australian police officers who participated in different missions in Timor-Leste. Integrating the insights from cultural analysis, the paper explores the specific challenges of bringing together police from different nations to work effectively within these operations.