Advances in long-range precision strike missiles, such as cruise missiles, ballistic missiles and hypersonic weapons, threaten the survivability of surface warships. In response, states are deploying submarines in the water column and expanding military activities on the seabed. Concepts such as “upward falling payloads” and networked “hydra” seabed installations envision prepositioned sensors and weapons emplaced on the continental shelf along an adversary’s coast. This chapter explores the legality of military operations on the continental shelf of a coastal state. The coastal state has sovereign rights and jurisdiction over the living and nonliving resources of the seabed and subsoil in accordance with the UN Convention on the Law of the Sea. Foreign military activities are generally permissible on the continental shelf of a coastal state so long as they observe due regard for the resource rights of the coastal state. Coastal states enjoy the exclusive right to construct artificial islands on their continental shelf but they lack competence to regulate military seabed installations and structures on the continental shelf.