Scholars have noted an increased reliance on extraterritorial criminal jurisdiction as a response to transnational criminal activity, the rise in treaty law, and the resultant moral obligations. Meanwhile, existing international legal commentary notes that there are difficulties attached to using extraterritorial offences as the primary tool to deter and combat Child Sex Tourism (‘CST’). While extraterritorial offences are recognised as one (albeit important) part of a spectrum of legal and socio-political sanctions against CST, serious obstacles remain to their effective implementation. Various scholars and commentators have identified the challenges involved in bringing charges related to extraterritorial CST offenses within the jurisdiction of the offender’s citizenship. Frederick Martens is an Australian citizen who was prosecuted under s 50BA of the Crimes Act 1914 (Cth), a provision inserted into the Act to prevent and punish CST. Martens’ experience exemplifies some of the common difficulties arising in prosecuting extraterritorial CST offences. He was convicted of having sex with a minor outside of Australia and sentenced to a term of imprisonment. It later emerged that there was additional evidence that cast significant doubt upon his guilt, and as a result of this fresh evidence, Martens was granted a pardon and released. The case serves as a warning regarding the difficulties of these trials and the dangers of ill-considered prosecutions. Concerns raised by the case are canvassed in the conclusion, including evidentiary concerns, issues inherent to relying on child witnesses, the time delay often involved in prosecuting CST offenders, fair trial concerns, and the problematic application of extraterritorial jurisdiction. This article aims to contribute to the existing body of research on the application of Australian CST laws and the wider international debate concerning the utility of extraterritorial CST offences, and will address certain related controversies regarding the extraterritorial application of criminal laws, including those regarding sexual offences committed by UN Peacekeeping personnel.