Marine currents are more predictable than wind and solar power. Because there are only small fluctuations in current speed and stream location with minimal changes in direction, ocean currents may be suitable locations for deploying energy extraction devices such as turbines. The kinetic energy of marine currents can be converted in much the same way that a wind turbine extracts energy from the wind, using various types of open-ﬂow rotors.The potential of electric power generation from marine tidal currents is enormous. Tidal currents are being recognized as a very promising resource to be exploited for a future sustainable scenario of electrical-power generation. Typically a mechanical gear system is used to increase the marine current power generation system(MCPGS) rotational speeds before being coupled to a permanent magnet synchronous generator(PMSG). The gear systems currently being employed suffer from significant long term maintenance and reliability issues. Hence, measures should be taken at the design stage to reduce the frequency and simplify maintenance procedures. The rotational speed of the turbine shaft could be geared up to reach the operational speed of a standard electric generator by a MG. The MG offers many advantages over its mechanical counterpart such as contact free torque production, no gear lubrication and inherent overload protection. Instead of mechanical transmission devices, the advent of magnetic gears means the less routine maintenance, simplifying the task substantially. This paper employs a MG as the speed-increasing device to connect the MCT and the PMSG. The MG is design for a very low speed ocean generation application. An accelerated diffuser is used to improve energy capture coefficient in the MCPGS. We shall describe the main features of the MCPGS based on the MG. The technological solution could lead to a feasible scheme for MCPGS in the future.