International law is clear on most issues associated with the conduct of marine scientific research (MSR) and hydrographic surveying but what is not clear is whether or not another State might conduct hydrographic surveys in an exclusive economic zone (EEZ) without the prior authorization of the coastal State. This paper reviews what is involved with MSR, hydrographic surveys and military surveys before reaching the conclusion that trends in recent decades with technology, the utility of hydrographic data and State practice require that hydrographic surveys in the EEZ should be under the jurisdiction of the coastal State. Paradoxically the arguments for military surveys in the EEZ being outside the jurisdiction of the coastal State appear stronger than those applying to hydrographic surveying. The paper offers some guidelines related to the conduct of MSR and hydrographic surveying in the EEZ but is not able to do so with regard to military surveys. This latter aspect requires further consideration outside the scope of this paper.