• The article examines the role of the seas in Sumerian and Akkadian royal inscriptions and literary texts from the third millennium BCE onwards. By tracing the presence of the sea in these texts, it becomes clear that the Upper and Lower Sea – or the Mediterranean and the Persian Gulf, though the former could shift geographically – could stand as terminal points for imperial control; as an obstacle or opponent to tackle; and moreover, as markers of distant, even constructed space. Overall, the sea functioned as both a real and imaged border within the Mesopotamian worldview.