As the world's largest carbon reservoir, the ocean holds enormous potential for storing massive quantities of carbon dioxide, yet technologies and strategies to enhance carbon sequestration require further in-depth development and evaluation. The Ocean Negative Carbon Emissions (ONCE) program aims to unleash the ocean's potential as a major carbon sink through cutting-edge technology and international collaboration. It seeks to forge a new pathway that integrates ecological restoration with carbon sink augmentation, leading the way toward ocean-based climate governance solutions.