International audienceMaritime Spatial Planning (MSP) is widely recognised around the world as a lever for sustainable development at sea. In practice, it is a new form of negotiation for the use of maritime space and its resources. To support shared decision-making, MSP requires information on the spatiotemporal dynamics of existing maritime activities. In this context, maritime surveillance, operated in real-time by the State (defence, fisheries monitoring) is a strategic source of data (AIS, VMS and radar) and information for planning purposes. While these data are growingly used by the scientific community, their contributions to MSP remains marginal. This article identifies the main reasons for this, drawing on 38 semi-directive interv...