Kampung Mandar is a village in Banyuwangi Regency that was labeled the most slum-like village in 2017. This designation was largely due to a smelly and polluted river, which significantly affected water quality. The purpose of this study was to analyze the water quality based on physical and chemical parameters. In situ measurements included salinity, pH, and temperature, while ex situ measurements included nitrite, nitrate, and orthophosphate levels. The youth of Kampung Mandar, in collaboration with the local government (Supertim), initiated efforts to clean the polluted river and transform the village's image from slum to clean. In recognition of these efforts, the Banyuwangi government supported the community by organizing a fish market festival in 2018 and 2019. Today, the cleanliness and beauty of Kampung Mandar have made it an attractive destination for culinary, cultural, and mangrove tourism. Salinity, pH, and temperature at three sampling points generally met river or marine water quality standards. However, nitrite, nitrate, and orthophosphate concentrations were often above acceptable limits. This is likely due to the river's proximity to densely populated areas, where improper household waste disposal contributes to pollution. Despite this, positive behavioral changes among residents have had a favorable impact on the river, which is no longer dirty or smelly—improving the aesthetic and environmental value of Kampung Mandar as a tourist destination. High water quality greatly enhances the tourist experience and supports the sustainability of tourism. Waters that are clear, ecologically balanced, and free of pollutants offer visual appeal and ensure the safety and comfort of visitors during recreational activities.