The rapid demand for goods shipping and increasing role of sea transportation services make countries that have sea territory developed sea transportation infrastructure. They do not only develop for transportation, exploitation of marine products, and tourism but also make seafront areas as the potential development of the new city of Seatropolis. This research used the qualitative and quantitative method through literature studies to identify parameters as a minimum requirement for the development of marine areas that can support the development of advanced new cities. After that, through a case study on the country of Indonesia which is a maritime country with the largest area of the sea obtaining the size of the initial investment cost of a city with the concept of Seatropolis. In the final stage of this research was in-depth interviews for validating the results of data analysis results. The results of the case study identify potentials in developing eco-town in the coastal area such as commercial area, residential, power plant, and industries through sustainable development concept. The total initial cost to develop Seatropolis cities was US$ 1,974,070,053.85. This research observation divided the operational costs into three phases of construction development. Each phase of 2023, 2025, 2027 consisted of US$ 18,888,781.62, US$ 33,872,403.81, and US$ 51,974,650.82. The government should include in the financing scheme for the initial cost of 59.38% and invest in operation and maintenance around 31.74% with obtained revenue of 33.96%. This scheme generates optimum IRR of about 15.41%.