The Ottoman Mediterranean was a place of intense imperial interest in the eighteenth century, yet our understandings of that century are still overshadowed by European naval ascendance, the defeat at Çeşme in 1770, and the beginnings of reform under Selim III . However, this paper will demonstrate the eighteenth century was a period of significant investment in naval resources, and development in maritime legal practices. Linked to new notions of maritime sovereignty and territoriality that emerged from concurrent ideas on land following the treaties of Carlowitz (1699) and particularly Passarowitz (1718), naval protection missions (Bahr-ı Sefid muhafazası) took on a new purpose of not simply defending Ottoman coasts and waters, but asserting maritime territoriality. The endemic threat of foreign corsairs, particularly Maltese, and local pirates, especially Maniots, necessitated increasing investment in naval patrols as a regular safeguard for trade and sovereignty, ensuring a regular imperial presence in the coastal provinces. In addition to this threat, the numerous wars between friendly European powers, particularly the British and French, saw increasingly destructive privateering wars that affected Ottoman shipping and subjects. This resulted from the 1690s in 'maritime regulations', şurut-u derya, that forbade armed European ships from entering extended Ottoman maritime space in times of war. Based on research on the administrative and legal documents relating to the Ottoman navy throughout the eighteenth century, this paper will chart these two concurrent developments - enhanced naval patrols and legal innovation - between 1690 and 1790 to demonstrate that the Ottoman state reacted to both foreign and domestic challenges in its maritime spaces (coastal and in the open sea) in the Mediterranean by using force, law, and diplomacy to enforce and consolidate its claims over its littoral territory and maritime trade routes and to solidify a dependent relationship local actors in the provinces.