This paper presents a hybridized triboelectric-electromagnetic generator based on heaving point absorbers to harvest the energy of water waves. The device consists of a cylindrical freestanding grating triboelectric generator (TENG) and a 3-phase tubular electromagnetic generator (EMG). The proposed system incorporates a slider which is capable of moving through a stator under the motion of a floating buoy. The floating component can heave up and down while facing water waves without being affected by the wave direction. The performance of the TENG and EMG units and corresponding electrical outputs are evaluated under various structural, dynamical, and electrical conditions. It is shown that the number of segments in the TENG unit, phase number in the EMG unit, and motion frequency in both harvesters are the key elements in the outputs of the hybridized system. For the first time, the effect of irregular wave motion on the TENG harvester performance is systematically explored using a well-known wave spectrum. Also, the performance of the hybridized system for charging a storage unit is evaluated in details. The presented energy harvester shows a great potential toward harvesting the energy of water waves as well as hydrodynamic sensing applications. In addition, this research provides a framework for the exploration of irregular wave motion in TENG-based energy harvesters.