Monitoring and maintaining aquatic environment is the universal need and Underwater Acoustic Sensor Networks (UASN) is an emerging technology plays a major role in acoustic data acquistion. The data acquisition is challenging issue in UASN due to its communication characteristics. Though, there are several geo-opportunistic routing protocols were explored to improve the data acquisition it can be still improved by enhanced routing technique. The existing Geo-graphical depth adjustment routing (GEDAR) uses Global Positioning System(GPS) based notes for improving data acquisition, however it consumes more energy and increases overhead. We make an attempt to study about efficient data acquisition process and its path reliability. The proposed Itinerary aware routing protocol(IARP) acquires neighboring node’s information for constructing efficient and reliable link with minimum information which improves data delivery ratio with minimum energy consumption. The proposed IARP increases 11% packet delivery ratio and reduces delay by 13%, and energy consumption by 9% comparing with existing GEDAR based algorithm. IARP also performs better than Depth based routing (DBR).