Coral reefs are complex, biologically diverse, and highly valued ecosystems that are declining worldwide due to climate change and ocean acidification, overfishing, land-based sources of pollution, and other anthropogenic threats. To assist policymakers and resource managers at international, national, and local levels in effectively implementing ecosystem approaches to sustainable management and conservation of coral reefs and their biodiversity, it is necessary to have timely, unbiased integrated ecosystem observations about the conditions of coral reefs and the complex physical and biogeochemical processes supporting them. To provide these interdisciplinary ecosystem observations, an International network of Coral Reef Ecosystem Observing Systems (I-CREOS) is proposed that will organize and build upon existing coral reef observation systems being developed around the globe. This paper uses examples of some developing observation systems to demonstrate some of the approaches and technologies available for acquiring biological, physical, and geochemical observations using combinations of visual surveys, moored instrument arrays, spatial-hydrographic and water quality surveys, satellite remote sensing, and hydrodynamic and ecosystem modeling. This fledgling, and hopefully expanding, network of observing systems represents the early stages of an integrated ecosystem observing system for coral reefs capable of providing policymakers, resource managers, researchers, and other stakeholders with essential information products needed to assess various responses of coral reef ecosystems to natural variability and anthropogenic perturbations. While significant challenges and gaps in the I-CREOS network remain, it demonstrably fulfills the requirements of an operational, integrated, interdisciplinary, coastal component of GOOS. Continued support, further development, and open expansion of this emerging network are encouraged and needed to ensure the continually increasing value of the network’s observational and predictive capacity. With common goals to maximize versatility, accessibility, and robustness, the existing infrastructure and capacity provide a foundation by which increased global cooperation and coordination could naturally lead to a globally comprehensive I-CREOS.