This chapter traces the successive strategies developed by the Forensic Oceanography project we have led since 2011 to document and contest the conditions leading to large-scale deaths of migrants at sea. The chapter first traces the aesthetic regime within and against which the project sought to position itself. It then analyzes the project’s shift from the documentation of specific practices of actors at sea leading to cases of deaths (such as the “Left-to-die Boat”), to the reconstruction of the lethal effects of state policies (such as the ending of the Mare Nostrum operation), and finally its contribution towards the WatchTheMed Alarm Phone, a 24/7-operating nongovernmental emergency phone line allowing to intervene directly to support migrants in distress at sea. While European agencies such as Frontex operate a state-centered “risk analysis” in the aim of neutralizing the “threat” illegalized migrants are constructed as constituting, Forensic Oceanography has forged a form of migrant-centered “counter-risk analysis,” which seeks to contest the violence of borders and mitigate the risks that migrants encounter as a result of state policies. The Mediterranean mobility conflict, this chapter demonstrates, is also fought out through conflicting knowledges and mediations of the border.