Solar interfacial vapor generation based on low evaporation energy requirements is an effective technology to speed up water purification under natural sunlight, offering great potential to alleviate the current global water crisis. The external electric field and hydrogel are two independent methods enabling low‐energy water evaporation. However, the complicated external equipment for generating an electric field and the restricted activation area of hydrogels significantly limit their practical application in steam generation. Thus, a piezoelectric fiber membrane is embedded into a highly hydratable light‐absorbing poly(vinyl alcohol) (PVA) hydrogel for synergistic water activation. The integrated evaporator is capable of continuously converting the wave energy reserved in the ocean into electrical energy, activating the water in the hydrogel. It is found that the activation effect leads to an improvement of over 23% compared to a non‐piezoelectric hydrogel evaporator. This work provides an evaporation prototype based on the synergistic water activation of wave‐triggered electricity and highly hydratable hydrogel. A self‐powered solar water purification technique containing an all‐in‐one composite film evaporator composed of light‐absorbing hydrogel and piezoelectric fiber membrane, which triggers water activation in the hydrogel to synergistically combat the intrinsically high energy demand for water vaporization, thus delivering a high steam generation rate of 2.702 kg m−2 h−1 with an improvement of ≈23% compared to the non‐piezoelectric evaporator under one sun, is presented.