Wells turbine is a self-rectifying axial air turbine, which consists of symmetrical aerofoil at 90° stagger. It is used to extract power from the bidirectional airflow inside an oscillating water column. Generally, the performance of the turbomachines is affected by the turbulence intensity. In this numerical study, the effect of turbulence intensity on the performance of large-scale Wells turbine is investigated. Different values of turbulent intensities were applied at the inlet and their influence on the aerodynamic characteristics is analysed. A single blade with periodic boundary condition is taken as the computational domain for numerical analyses. The simulation results of the reference geometry were compared with existing experiment and numerical results. The performances of the Wells turbine with different turbulent intensities were computed by solving Reynolds-averaged Navier-Stokes (RANS) equations. Finally, the results were compared and analysed. It is found that the large-scale Wells turbine (LSWT) performance is unaffected by the varying inlet turbulence intensity. Furthermore, a marginal improvement in the performance was observed with an increase in turbulence intensity.