Being one of the specially protected areas declared by General Directorate of Natural Assets Protection, G&ouml / cek Bay is threatened by increasing boat tourism and insufficient legal practices. Large scale measures are being planned for decreasing the pollution and protecting the region. For a sustainable coastal management, technical, social, political and economic tools are needed to be used. For environmental investments, it is necessary that they should be identified in monetary terms. The aim of this study is to determine the benefits and costs of the management alternatives to improve environmental quality in G&ouml / cek Bay to aid decision makers. In the study, the environmental benefits that can be obtained with improved water quality and restated marine ecosystem was calculated using the Choice Experiment Method. Data analyses are made using Multinomial Logit analysis. The results showed that, for improvements in water quality local residents are willing to pay 18 TL/month and tourists are willing to pay 16.6 TL/tour. For improvements in marine life local residents are willing to pay 14.8 TL/month and tourists are willing to pay 11.2 TL/tour. The total value that can be obtained from these stakeholders is calculated as 751,140 TL/year. This amount enables the investments to amortize themselves in 21 years. With this study, it has been seen that the obtained results will pave the way for new policies and measures against the deterioration of the marine environment of G&ouml / cek.