NEPTUNE Canada is the world’s largest cabled seafloor scientific observatory and has been in operation since 2009. The system consists of a large network of instruments that are located at variable water depths and different oceanic and tectonic environments and continuously delivers data to researchers and the public via the internet. The establishment of NEPTUNE Canada is for the purpose of addressing scientific questions that are categorized into five themes: earthquake processes and plate tectonics, subsea geofluids, marine life and climate change, deep sea ecosystems, and engineering and information sciences. In order to promote international collaboration and accelerate scientific research to the maximum extent possible, the system makes its usage open to all researchers in the world and all its data freely accessible, in a fashion unprecedented in scientific history. Such a multidisciplinary and fully open large system of complexity demands advanced governance and management as well as an excellent culture of scientific research.