Ocean currents represent a potentially notable, currently untapped, reservoir of energy. The regions with strong current velocities such as narrow straits connecting two water bodies exhibit high current energy potential. The Bosphorus, connecting the Black Sea to the Sea of Marmara, is a typical narrow sea strait that generally exhibits a two-layered flow pattern. The present study aims at revealing annual current power potential of the Bosphorus by means of three dimensional numerical model results, calibrated with one-year current measurements. After determining the most energetic regions in the strait, the cross-sectional variations were also analyzed at two energetic sites.