The Ocean Observatories Initiative is made up of seven major research components in the North and South Atlantic and Pacific: the Cabled Array and its two sub-arrays – Cabled Axial Seamount and Cabled Continental Margin – on the Juan de Fuca plate; the Coastal Endurance Array off the coast of Oregon and Washington; the Coastal Pioneer Array off the coast of New England; Global Argentine Basin Array in the South Atlantic Ocean; the Global Irminger Sea Array off the coast of Greenland; the Global Southern Ocean Array SW of Chile; and Global Station Papa in the Gulf of Alaska. Each array is composed of a number of sites at which different stable and mobile platforms are deployed. Array locations and configuration were designed based on input from the scientific community in order to study a set of specific regional and collectively global science questions.