The objective of this paper is to compare the performances of the themes, which could be used for wave energy conversion in the near future, under various irregular wave conditions. The turbines included in the paper are as follows: (a) Wells turbine with guide vanes; (b) impulse turbine with self-pitch-controlled guide vanes; (c) impulse turbine with fixed guide vanes. In this study, experimental investigations were carried out to clarify the performances of the turbines under steady flow conditions, and then a numerical simulation was used for predicting the performances under irregular wave conditions with various significant wave heights. As a result it was found that the running and starting characteristics of the impulse turbines could be superior to those of the Wells turbine. The objective of this paper is to compare the performances of the themes, which could be used for wave energy conversion in the near future, under various irregular wave conditions. (A) Wells turbine with guide impasted turbine with self-pitch-controlled guide vanes; (c) impulse turbine with fixed guide vanes. In this study, experimental investigations were carried out to clarify the performances of the turbines under steady flow conditions, and then numerical simulation was used for predicting the performances under irregular wave conditions with various significant wave heights. As a result it was found that the running and starting characteristics of the impulse turbines could be superior to those of the Wells turbine.