Water transport was the earliest mode of transport in ancient Mesopotamia. Thanks to the Tigris and Euphrates rivers, which run along the whole length of Mesopotamia, and a network of canals, river transport facilitated communication, exchange, as well as cultural and military contacts between towns. This paper focuses on the riverine transport in Mesopotamia and its development from the Ubaid (5900-4200 BC) to the Neo-Babylonian period (626-539 BC). The importance of river transport in Mesopotamia is discussed, considering its role as a means of communication, exchange of goods and ideas, and a factor influencing the sociopolitical transformation in the region. Watercraft is discussed to the full extent, with particular emphasis on different types of ships and their functions. The chronological development of watercraft in Mesopotamia is also analysed based on boat models, cuneiform texts, and representations of boats in the art. [ABSTRACT FROM AUTHOR]