Introduction: Climate change is a global challenge that requires a comprehensive policy response, including environmental economic instruments such as carbon taxes and carbon trading. As a developing country, Indonesia plays an important role in reducing greenhouse gas emissions through its Nationally Determined Contribution (NDC) commitment. However, the implementation of carbon trading still faces various legal challenges, particularly regarding legal certainty, climate justice, and environmental protection. Research Method: This study uses normative legal research methods with conceptual approaches, laws and regulations, and policy approaches. Legal materials are obtained through literature studies that include laws and regulations, journal articles, and scientific proceedings related to environmental law and carbon regulation. Data analysis was carried out qualitatively using a descriptive-analytical method. Results: The results of the study show that carbon trading regulations in Indonesia still face challenges in the form of policy disharmonization, supervision gaps, and suboptimal legal protection for investors and business actors. The principle of climate justice demonstrates the importance of proportionate distribution of responsibilities for reducing emissions as well as protecting vulnerable groups. Environmental protection is the main goal in ensuring the sustainability of ecosystems and preventing environmental damage due to carbon-based economic activities. Conclusion: The integration of legal certainty, climate justice, and environmental protection is an important factor in strengthening carbon trading regulations in Indonesia. Cross-sectoral policy harmonization is needed to create a transparent, fair, and sustainable carbon trading system.