In the world of computer networks, underwater areas are a special setting that brings difficulties because of things like sound speed changing, node moving around, and limited node life. Since aerial networks are getting more crowded and overused, the study of underwater networks has become important. This thesis looks at the problems and possibilities in underwater networks, especially for packet routing within the network layer. We aim to assess and contrast different routing protocols that NS2 supports, looking at main performance metrics like end-to-end delay, energy consumption, and packet delivery ratio (PDR). By concentrating on these measurements we wish to highlight the pros and cons of different routing protocols for underwater networks. Along with that, we are also proposing an energy-efficient end-to-end IoUT architecture that explains how a small payload of data gets transmitted from underwater sensor nodes to the LoRa gateway. This would help in progressing technology related to underwater network systems.