The scope of the present work is the techno-economic study with concern for the environmental issues and the investigation of the viability of an offshore wind farm in the Greek sea area, northeast of the island of Limnos. In the context of this study, the wind data, the suitable location for the installation of the wind turbines beyond nature protected areas, the type of the wind turbines, the losses due to wind turbines interaction, and the visual impact at the respective study areas are analyzed. Moreover, reliable costing models are used and applied, internationally recognized for techno-economic studies of offshore wind farms. Thereafter, the viability of the project is studied through investment benchmarks. This means that specific economic indices are estimated indicating whether the realization of such an investment is viable or not. In conclusion, based on the analysis performed in this study, it is noted that in the Greek archipelago and especially at the island of Limnos, there is a sufficient offshore wind potential at low depths and at relatively short distances from the shore. These circumstances are necessary conditions for the development of offshore wind farms in these areas. Moreover, economic estimations based on current data of grants, taxation, interest rates, etc., showed that the investment is sustainable, having a cost of energy production equal to 87.92 €/MW h.