Recently, underwater wireless sensor networks (UWSNs) have emerged as a promising networking technique for various underwater applications. An energy efficient routing protocol plays a vital role in data transmission and practical applications. However, due to the specific characteristics of UWSNs, such as dynamic structure, narrow bandwidth, rapid energy consumption, and high latency, it is difficult to build routing protocols for UWSNs. In this paper, We propose a location aware opportunistic routing algorithm for under water communication. We analyse three main problems in under water communication; forwarding set selection forwarding set ranking to handle FSR problem, void handling method to handle the communication void (CV) and overhear and suppression procedure to deal with duplicate forwarding suppression (DFS) problems. The importance of the work is that it will provide an energy efficient pressure based opportunistic routing algorithm for wireless sensor network (UWSN). The routing protocol has been implemented in the ns2-AqaSim simulator and testbed for measurement of the performance metrics of the UASN. The simulation results showed that the novel routing method throughput has increased by 16%, 33%, and 55% when compared with SUN, VBF and DF method. It can effectively improve the throughput of nodes, balance positioning performance as well as energy use efficiency, and optimize the positioning result of UWASN.