Underwater Wireless Sensor Networks (UWSNs) are finding different applications for offshore
exploration and ocean monitoring. In most of these applications, the network consists of significant
number of sensor nodes deployed at different depths throughout the area of interest. The sensor nodes
located at the sea bed cannot communicate directly with the nodes near the surface level; they require
multi-hop communication assisted by appropriate routing scheme. However, this appropriateness
depends not only on network resources and application requirements but also on environmental
constraints. All these factors provide a platform where a resource-aware routing strategy plays a vital
role to fulfill the different application requirements with dynamic environmental conditions. Realizing
the fact, significant attention has been given to construct a reliable scheme, and many routing protocols
have been proposed in order to provide an efficient route discovery between the sources and the sink.
In this paper, we present a review and comparison of different algorithms, proposed recently in order to
fulfill this requirement. The main purpose of this study is to address the issues like data forwarding,
deployment and localization in UWSNs under different conditions. Later on, all of these are classified
into different groups according to their characteristics and functionalities.