Early marriage remains a significant social issue with implications for children’s health, education, and welfare. Although Law Number 16 of 2019 establishes 19 years as the minimum marriage age for both men and women, early marriage continues to occur in several areas, including Nalo Tantan District. This study aims to examine the strategies employed by the Office of Religious Affairs (KUA) of Nalo Tantan to prevent early marriage and identify the challenges encountered in their implementation. A descriptive qualitative approach was employed, with data collected through in-depth interviews with the Head of KUA, marriage registrars, and religious counselors, as well as field observations and documentation. The findings indicate that KUA Nalo Tantan implements various preventive strategies, including legal education and dissemination of Law Number 16 of 2019, premarital counseling, cross-sector collaboration, family-based approaches, persuasive mediation, administrative verification, and cultural engagement through religious and traditional leaders. Nevertheless, implementation is constrained by limited educational and social literacy, economic pressures, adolescent peer influences, and social media exposure. The study concludes that effective prevention of early marriage requires stronger and sustained collaboration among KUA, local government, educational institutions, religious and traditional leaders, and the wider community to support the implementation of Law Number 16 of 2019.