This study aims to analyze the legal framework that governs responsibility for the damage to public facilities in coastal areas from the perspective of the theory of the rule of law and examine how the principles of sustainable development can strengthen legal accountability in the protection of coastal infrastructure. Although normatively Indonesia already has various regulations governing the management of coastal areas, the environment, spatial planning, and local government, in practice there are still gaps between norms and implementation, especially in the division of authority, supervisory mechanisms, and accountability effectiveness. This research uses normative legal research methods with legislative, conceptual, and case approaches. The analysis was carried out on laws and regulations related to the management of coastal areas, environmental protection, spatial planning, and administrative, civil, and criminal responsibilities. The framework of analysis is based on the Theory of the State of Law which emphasizes the principles of legality, accountability, and protection of citizens' rights, as well as the Theory of Sustainable Development which integrates the principles of prudence, intergenerational justice, polluter pays principle, policy integration, public participation, and ecological restoration. The results of the study show that normatively the Indonesian legal framework has provided a legal basis for claiming responsibility for damage to coastal public facilities, both through administrative, civil, and criminal mechanisms. However, its effectiveness is still hampered by overlapping authority, weak coordination between agencies, and the lack of optimal application of sustainable development principles in coastal infrastructure planning and supervision. The integration of sustainable development principles into the national legal system has been proven to expand the scope of accountability from reactive to preventive and adaptive to climate change risks. Thus, strengthening coastal infrastructure protection requires synergy between the principles of the rule of law and the principles of sustainable development in order to realize a more responsive, fair, and long-term oriented legal accountability system.