The increase in economic activity in the Kejawanan Nusantara Fishing Port area has created quite complex environmental problems. To address these problems, the Kejawanan Nusantara Fishing Port has implemented the K5 principles (cleanliness, aesthetics, security, order, and occupational safety). However, the extent of their success remains uncertain. This study aims to evaluate the effectiveness of implementing the K5 principles as the basis for environmental control at the Kejawanan Nusantara Fishing Port, Cirebon City. This study used a descriptive quantitative and qualitative evaluative approach through field observations, in-depth interviews, focus group discussions, and the distribution of questionnaires to 75 respondents consisting of port managers, security officers, cleaning officers, government agencies, fishermen, business actors, and marine tourism visitors. The evaluation results showed that the implementation of the K5 principles at Kejawanan Nusantara Fishing Port was in the good category with an average score of 3.82. The highest score was obtained for the cleanliness aspect (4.05) and the lowest for the orderliness aspect (3.55). The success factors in environmental control were supported by the availability of a wastewater treatment plant (WWTP), the involvement of cleaning personnel, and the implementation of occupational safety standards. The main obstacles were limited human resources, weak coordination between agencies, and low awareness of environmentally friendly behavior among port users. Priority strategies for environmental control were identified in the ecological dimension, such as improving WWTP facilities, solid waste management, and port drainage rehabilitation.