Fishing for subsistence constitutes a livelihood safety net for poverty, malnutrition, and gender inequality for populations dependent upon aquatic foods around the world. Here, the authors provide global estimates showing that almost the same amount of small-scale fishers engage in subsistence fishing at some point during the year as in commercial employment and use subsistence estimates to measure small-scale fisheries’ livelihood safety net function. In 2016, the authors estimate that 52.8 million people were engaged in subsistence fishing at some point during the year, while another 60.2 million people were commercially employed (90% of global fisheries employment). From 14 country case studies, it was possible to estimate that the subsistence catch provided an average apparent intake of six nutrients critical for positive health outcomes, equivalent to 26% of the recommended daily nutrient intake for 112.5 million people, higher than the national average contribution of beef or poultry. The case studies came from Illuminating Hidden Harvests: The Contributions of Small-Scale Fisheries to Sustainable Development, a global study uncovering the contributions and impacts of small-scale fisheries through a multidisciplinary approach to data collection and analysis.