Marine environmental monitoring relies on distributed sensor networks, yet sustainable power supply remains a critical challenge due to the limitations of batteries and inefficient energy harvesting under low-frequency wave conditions. While triboelectric nanogenerators (TENGs) show promise for blue energy harvesting, they often suffer from the trade-off between power output and durability, along with pulsed alternating-current output unsuitable for direct-current electronics operation. Here, we present a hybrid blue energy harvesting device based on a constant-voltage triboelectric nanogenerator (HCV-TENG). The system incorporates a soft-contact constant-voltage TENG (SCV-TENG) for wave energy conversion and a non-contact constant-voltage TENG (NCV-TENG) for wind energy harvesting, producing regulated direct-current output through an integrated rectification and phase modulation mechanism. The SCV-TENG achieves an average power density of 31.2 W/m3 at 2 Hz and acts as a charge pump, boosting the output of NCV-TENG by over 160.2 times. In water waves, the system delivers an in situ average power density of 7.9 W/m3. Remarkably, the HCV-TENG shows only 0.68% performance loss after 2.33 million cycles, demonstrating excellent longevity. By powering commercial sensors and enabling wireless data transmission, the HCV-TENG offers a robust and efficient solution for self-powered systems in marine environments, overcoming key limitations in output stability and device durability.