Covering 70.8% of the world’s surface, the ocean’s vastness constitutes a scientific and technical challenge that requires organised systems on an international scale. IUEM is involved in this process as coordinator of the SNO-ARGO-France system, which aims to monitor the physics of the world’s oceans, and as co-sponsor of the national structuring of deep-sea observation for monitoring seismic hazards (MARMOR and OHASISBIO).