Many states have enacted extra-territorial child sex tourism (CST) offences. Despite the existence of these offences, some states, including Australia and the United Kingdom, continue to privilege territorial competence as the basis of criminal jurisdiction. However, many destination countries for CST in South-east Asia lack the capacity to support prosecutions in this crime. This article explores the utility of partnerships between local and international law enforcement agencies and NGOs to facilitate prosecution in the jurisdiction of the offence. Through a case study of Cambodia, the article argues that such partnership arrangements provide the resources and integration required to enable sexual offences against children, by foreign offenders, to be prosecuted. NGOs undertake complex strategies to address the immediate needs of exploited children, while seeking to maintain their capacity to influence government policy. The risks, challenges, and sustainability of such partnerships are discussed, along with wider implications for South-east Asia. Abstract published by arrangement with John Wiley & Sons.