The SOOS mission is to facilitate the collection and delivery of essential observations on dynamics and change of Southern Ocean systems to all international stakeholders (researchers, governments, industries), through design, advocacy and implementation of cost-effective observing and data delivery systems. SOOS is an international initiative of the Scientific Committee on Antarctic Research (SCAR) and the Scientific Committee on Oceanic Research (SCOR). Developed over many years, SOOS was officially launched at the end of 2011 with the opening of the International Project Office, hosted by the Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Australia. Since then, SOOS has built a network of stakeholders and contributors, all working together to achieve the community-defined mission and objectives. The SOOS vision is that all stakeholders will have access to a sustained of observational coverage that will provide a foundation to advance understanding of the Southern Ocean and to address critical societal challenges.