The Global Ocean Observing System (GOOS) is a sustained, collaborative platform providing essential data on physical, chemical, and biological ocean variables. Led by the Intergovernmental Oceanographic Commission (IOC) of UNESCO and co-sponsored by the World Meteorological Organization (WMO), UN Environmental Programme (UNEP), and International Science Council (ISC), it supports climate monitoring, ocean health, and safe, sustainable marine development. GOOS coordinates global monitoring networks and defines requirements to ensure data delivers actionable information for science and policy.