The expansion of information and communication technologies and the growth of online transactions have—alongside their economic and social benefits—paved the way for the emergence and proliferation of novel forms of fraud. Due to the speed and ease of commission, perpetrator anonymity, the cross-border nature of the crime, the difficulties involved in detection and prosecution, and the constantly evolving nature of criminal methods, online fraud poses a serious challenge to economic security and public trust. Employing a descriptive-analytical method and a comparative approach, this study examines mechanisms for preventing online fraud under Iranian law, with reference to English law. Within this framework, situational crime prevention and its components—such as increasing the difficulty of commission, raising the risk of detection, reducing the benefits derived from the crime, minimizing provocations, and removing excuses for offending—are highlighted. The findings indicate that Iranian law possesses significant potential to prevent this crime through penal regulations, supervisory measures, technical interventions, and the role of responsible institutions; however, the effectiveness of these measures has been undermined by weaknesses in the coordinated implementation of preventive policies, limited public education and awareness, institutional fragmentation, and insufficient private-sector participation. In English law, a prominent role is played by the integration of legal, technical, educational, and collaborative measures, alongside a focus on managing criminal opportunities, identifying fraudulent behavior, and increasing the risks associated with committing the offense. A comparison of the two systems reveals that enhancing prevention in Iran requires a comprehensive, coordinated, and multi-layered policy that draws appropriately upon the experiences of the UK.