In this study, a new concept of a small-scale piezoelectric wave energy harvester operating on the acceleration-driven principle is proposed, designed, and tested. Six piezoelectric generators placed in the enclosure are used as energy conversion devices due to their high-frequency response and capability of withstanding relatively large strain. The advantages of the proposed device are that it can operate at deployment sites with consistent medium/small wave energy flux and can naturally float on the water surface. Since the proposed wave harvester is self-generating, adding an external source is unnecessary, which makes the harvester lightweight, cost-effective, and suitable for operation in remote rivers and lakes. Feasibility studies of the preliminary mechanical design were performed using numerical modeling complemented with laboratory and field experiments. The maximum generated power was calculated from the digital record of the measured voltage across the optimum load resistance. The final prototype of a single piezoelectric wave energy harvester could generate a maximum of 5 mW in the field experiments. A feasibility study of arrays of convertors was also investigated experimentally.