In underwater acoustic sensor networks (UWASN), energy-reliable data transmission is a challenging task. This is due to acoustic transmission disturbances caused by excessive noise, exceptionally long propagation delays, a high bit error rate, limited bandwidth capability, and interference. One of the most important issues of UWASN for research is how to extend the life span of data transmission. Data transfer from a source node to a destination node in UWASN is a complicated topic for researchers. Many routing algorithms, such as vector base forwarding and depth base routing, have been developed in past years. We propose a genetic algorithm-based optimization method for improving the energy efficiency of data transmission in the routing path from a source node to a destination node.