The underwater wireless sensor networks have found many applications in today's world as they are used in medical applications, sea exploration, military applications and many more. With the advancement in the underwater wireless sensor networks technology, new research challenges are found that are to be resolved like how efficient routing can be done without sacrificing energy consumption of the sensor nodes, how the deployment of the sensor nodes should be done and so on. Due to the movement of sensor nodes with the water currents, the deployment and routing becomes a difficult task. In this paper, various routing protocols like Information Carrying routing protocol, Depth Based routing protocol, Constraint Based Depth based routing protocol, Directional flooding routing protocol are discussed and a comparative analysis of these routing protocols on the basis of various parameters like localization information, network topology, and use of control packets, network architecture used is presented.