The Helical Savonius hydrokinetic turbines (HSHKT) are regarded as the beneficiary equipment to increase the power generation in low head rivers. This study investigates the performance of HSHKT arranged in arrays. Firstly, performance analyses of two HSHKT rotors are experimentally performed, arranged in inline formation along the fluid flow direction, for different spacing between them (L). These spacing are considered 3D (D = rotor diameter), 3.5D, 4D, 4.5D, 5D, and 5.5D. Experiments are performed in a hydraulic flume of 6 m length at 0.5 m/s velocities for different loading conditions. The optimum performance (i.e., coefficient of power and coefficient of torque) of both HSHKTs together is obtained at a distance of 4D. Consequently, the study is simulated through the ANSYS-CFX for 0.5 m/s upstream velocity and optimum performance is validated at L = 4D. Further, the study is extended in ANSYS-CFX for three HSHKTs arranged in arrays of different patterns, namely triangular and staggered formation. The analysis is performed for different velocities and varying distances between them. It is observed that at a 4D distance, the optimum performance of the three HSHKTs is achieved. Moreover, it is also found that HSHKT performance is better in staggered formation compared to the triangular formation.