Ocean sustainability initiatives – in research, policy, management and development – will be more effective in delivering comprehensive benefits when they proactively engage with, invest in and use social knowledge. We synthesize five intervention areas for social engagement and collaboration with marine social scientists, and in doing so we appeal to all ocean science disciplines and non-academics working in ocean initiatives in industry, government, funding agencies and civil society. The five social intervention areas are: (1) Using ethics to guide decision-making, (2) Improving governance, (3) Aligning human behavior with goals and values, (4) Addressing impacts on people, and (5) Building transdisciplinary partnerships and co-producing sustainability transformation pathways. These focal areas can guide the four phases of most ocean sustainability initiatives (Intention, Design, Implementation, Evaluation) to improve social benefits and avoid harm. Early integration of social knowledge from the five areas during intention setting and design phases offers the deepest potential for delivering benefits. Later stage collaborations can leverage opportunities in existing projects to reflect and learn while improving impact assessments, transparency and reporting for future activities.