To reduce deployment and maintenance costs, a novel wave energy converter (WEC) is proposed for mooring-less sensor buoys. The design concept is based on a small size WEC capable of harvesting wave energy without mooring, which can reduce the installation cost. The proposed wave energy converter consists of a submerged and a floating body, and the submerged body is a self-rectifying wave-induced turbine that uses the rise and fall of waves to turn a rotor. The rotor of the turbine has flap-type blades, which allows a self-rectifying rotation with rising and falling of waves. In this paper, the dynamics of the system is modeled by hydrodynamic equations, and simulations are carried out based on the dynamic model to determine the optimal design parameters of the system. In addition, the power generation in regular and irregular wave conditions and efficiency in irregular waves of the system are estimated. To verify the results of the simulation, a prototype of the system is implemented and tested in a sea trial. The results demonstrate the feasibility of the proposed wave energy converter. (C) 2017 Elsevier Ltd. All rights reserved.