The exploration of hydrokinetic energy has received significant attention in recent years. The cross-flow turbine-based Savonius rotor is popular for its excellent starting capability and moderate conversion efficiency. The present work numerically investigates the assessment of hydrokinetic energy utilization by deploying the circular deflectors upstream of Savonius rotor placement. The results have also been compared to without deflector-augmented Savonius rotor. Two positions (equispaced) in the upstream and downstream sides of the placement of the turbine are selected. The results demonstrate the variations of the kinetic energy at different angular positions. It is also observed that the deflector-augmented Savonius rotor is about 179.01 and 40.65% more effective in energy utilization in the vicinity (X3–X2) and far-field (X4–X1) locations, respectively, compared to without deflector Savonius rotor. Further, the gain in the hydrokinetic energy for circular deflector-assisted Savonius rotor is more due to guided flow and backward drag force reduction on the returning side blade.