Maritime security in the Indo-Pacific region is strategically important to not only the surrounding states, but also those with an interest in its good governance, to support safe passage and natural resources extraction. Criminal threats, such as maritime piracy and illegal fishing, enabled by corruption and the potential for terrorism, undermine regional maritime security and therefore, there is incentive for states to respond cooperatively to secure the region. Drawing on broken windows crime theory, implicitly supporting the continuation of criminal threats within the region may enables exiting crimes to proliferate. With varying legal and political frameworks and interests across the Indo-Pacific region, achieving cooperation and harmonisation in response to regional maritime-based criminal threats can be challenging. As such, to respond to criminal threats that undermine maritime security, this article argues that from a criminological perspective, aligning states through existing international law enables cooperative regional responses. Indeed, given the prevalence of corruption within the region enabling serious criminal threats, harmonising through existing counter-corruption architecture may be a suitable platform to build from.