A number of renewable energy sources (RESs) are available but the electrical machineries were being used in some of the hydro-electrical power plants for a long time. Recently wind waves have been taken into consideration as one of the giant natural sources of energy. The oceanic wave sometimes called a wind wave has the high power density compared to the other popular RESs. Unfortunately, the conventional machineries are not suitable for the energy conversion from the sea wave. Therefore, advanced electrical machines are obvious for successful extraction of electrical power from the sea wave. As a result, a wide variety of new electrical machines have been proposed to convert the mechanical power from the oceanic wave into electrical power. Some of such electrical machines with their properties have been discussed in this chapter. In addition, a high power density linear generator has been presented in detail.