In sensor networks, energy plays a vital role during communication between the sensor nodes. The amount of energy available at a sensor node increases or decreases the life of the network. A group of sensor nodes can share their information, only when they are active and alive that is they have enough energy to communicate. Over the past few years researchers have been involved in conserving energy by designing and proposing techniques that consume less energy. In this paper, we propose an energy efficient geocast technique for underwater sensor networks. This work extends over the RMTG protocol. The ERMTG algorithm takes into account the current energy state of the nodes to select the next relay node. The transmission energy of a node depends on the distance between it and the next hop node to which it wishes to transmit. By preferring paths made of closer nodes, a routing algorithm may reduce the energy consumption, hence increasing a node’s life. The simulation results obtained, show that the proposed ERMTG protocol is able to decrease the energy utilization in the network as compared to the RMTG protocol under similar working environment. The ERMTG protocol is found to outperform the RMTG protocol on various parameters such as network energy, path energy and the number of dead nodes.