In this paper, I theorize the changing conceptualizations of sovereignty and citizenship from the Ottoman Empire to the Turkish Republic through a comparative analysis of two instances of naval accidents within Ottoman-Turkish waters, in 1912 and 1926. In 1912, an American ship, Texas, sank around the Ottoman port of Symrna in an accidental collision with a sea mine. Complicating discussions of legal jurisdiction, the ship’s captain was a Greek citizen, while most passengers were Ottoman, and the ship itself belonged to an American company. The ensuing debates on legal jurisdiction and attributing responsibility provide a unique perspective into inter-imperial politics of contested sovereignty and citizenship in the late Ottoman Empire period. This case also provides a window into how legal capitulations and extraterritorial privileges granted to European and American foreigners became implemented in practice in local Ottoman courts, and European legal discourses of ‘civilization’ and legal inferiority. In a similar incident in 1926, a French ship, Lotus, sank around the Greek island of Mytilene due to an accident. In this case, the newly independent Turkish state was able to leverage its position within the international community to insist on national jurisdiction in the aftermath of the Lausanne Treaty of 1923. The comparison between the two naval accidents, and the discursive and legal constructions of sovereignty by respective states and international organizations involved, reveals competing conceptions of sovereignty in the beginning of the 20th century, and unpacks the transformation of international legal approaches to sovereignty and citizenship. Identifying a shift from emphasizing civilizational progress to national independence and equivalence, the paper then discusses the implications of these competing conceptions of sovereignty, and how their logics are imbricated with each other even while their practices differ. This project is based on Ottoman, Turkish and American state archives, contemporary newspaper articles and analyses, and documents produced by international bodies involved in the cases.