Maritime security concerns in the South China Sea are increasing for several reasons: higher volumes of shipping traffic, protection of exclusive economic zone resources, piracy, terrorist threats, greater international scrutiny of ports and shipping, and the modernization of regional naval and coast guard forces. Coastal states and international user states have many overlapping interests in the South China Sea, for example, in promoting safe navigation through its busy sea-lanes. On other issues, in particular, antipiracy or anti-maritime terrorism measures, they have different views about the seriousness of the threats and the responses necessary to address them. This article examines the convergent and divergent maritime security interests of coastal states (China, Indonesia, Malaysia, and Singapore) and international user states (Australia, India, Japan, and the United States) in the South China Sea. It finds that multiple stakeholders pursuing diverse interests have yet to close the gap between goals and means of achieving maritime security.