<p>Ocean energy, with its abundant reserves, has garnered significant attention as a renewable energy source, due to its potential to address global energy challenge and mitigate environmental deterioration effectively. However, this immense potential has remained largely untapped due to the limitations of traditional energy technologies. The emerging triboelectric nanogenerator (TENG) technology, with demonstrated advantages over existing power-generation schemes, appears to be a potential game changer for harnessing low-frequency ocean wave energy. Here, we provide a comprehensive review of recent progress in harvesting blue energy with TENGs, starting from the overall development venation of the TENG technology in blue energy applications. We thoroughly discuss the current research status and associated key issues, ranging from the structural design and performance optimization of TENGs to the system integration for water wave energy harvesting. Finally, we identify the challenges and opportunities of nanogenerator-based blue energy harvesting and applications. As technologies continue to evolve at an accelerated pace, we anticipate significant performance advancement for the TENGs in future. We are confident that the TENGs will play a transformative role in ocean energy harvesting, creating substantial industrial values and societal benefits as humanity continues to unlock the vast potential of oceans.</p> Graphical abstract <p></p>