The increasing demand for electricity is the biggest alarm of the nations all over the world. These demands can be reached by using the non-polluting renewable resources and one such is ocean energy, which is still being explored. This paper analyses the flow through a turbine used in a tidal energy harvesting plant. The turbine used is a horizontal axis current turbine with three blades mounted to the hub. The Reynolds-averaged Navier-Stokes equation is solved to get the flow field and turbine performance using a commercial package Ansys CFX 15.0. The results are compared with the existing experimental results. The performance of the turbine can be improved by changing its vital parameters like hub pitch angle, inlet velocity, rotational speed and etc. Working on these turbine parameters, a set of power coefficient data are given for various tip speed ratio. © 2016 Taylor & Francis Group, London.