This study evaluates the application of blockchain technology to enhance environmental accountability in sustainable tourism reporting in Bali, as a response to the risk of greenwashing practices. Given that traditional reporting systems often lack standardization and are vulnerable to manipulation, this study aims to empirically test the impact of blockchain integration on accuracy, efficiency, and stakeholder trust. Using a quasi-experimental method with a sample of 60 tourism businesses divided into treatment and control groups, data was analyzed through system metrics, surveys, and interviews. The results showed that blockchain significantly improved reporting accuracy by 18.6% and accelerated verification time by 67% (9.4 days faster). Furthermore, the use of smart contracts was shown to increase stakeholder trust and reduce audit costs with a return on investment ratio of 2.8:1. Theoretically, this study validates how automation and data immutability strengthen environmental accountability structures in complex tourism governance. In conclusion, blockchain technology is effective in increasing transparency and reporting efficiency, although its adoption by SMEs remains hampered by cost and technical barriers. The practical implications of this research emphasize the importance of developing user-friendly interfaces as well as financial support to ensure inclusive digital transformation for the sustainability of the tourism industry.