Military and intelligence-gathering activities, MSR and hydrographic surveys in an EEZ are problematic and controversial issues. There are at least two reasons for this situation. Firstly, the unresolved territorial and maritime boundary disputes mean that jurisdiction over an EEZ may be unclear. States may conduct all kinds of military operations and marine research in areas that might be claimed by other states. Secondly, some of the key terms and key expressions to define and regulate these activities under the United Nations Convention on the Law of the Sea (UNCLOS) are ambiguous. This creates opportunities for countries to interpret UNCLOS for their own interest. In the past few years, some actual incidents have shown conflicts of interest between different countries. This paper discusses the nature of these conflicts and the main concerns of the opposing parties.