Turbine blade thickness is limited by blockage and trailing edge losses, and are damaged due to high aerodynamic loadings. Safe turbine blade design needs a comprehensive knowledge of the exciting forces. This work investigates a mixed flow turbocharger turbine to study the effects of blade thickness distribution on the aero-structural performance. Three-dimensional flow field of the turbine was calculated using a CFD model in ANSYS CFX V.17. The blade structural responses are determined using an FEA model in ANSYS static structural module. Validation is performed by reference to experimental data carried out in Imperial College London on a dual turbocharger turbine. The results are presented to describe how and why the turbine aerodynamic and structural behavior varies with thickness under transonic conditions. On higher spans shock is more distributed to the passage but it has lower intensity. Thicker leading edge leads to more drop in Mach number through the bow shock. Higher distance of maximum thickness location from the leading edge caused the smaller separation bubble on the suction surface.