The underwater microgrid is becoming an emerging application for the ocean energy, which integrates ocean current energy converter systems, underwater loads, and the onshore main utility. The multi-layer hierarchical control is employed to maintain the underwater microgrid stability. Under this control architecture, the wireless communication networks between the centralized controller and the local controllers require a detailed evaluation in the underwater environment. This paper evaluates the most conventional wireless communication network technologies for data transmission in the underwater microgrid. First, the different communication modulation technologies and antenna configurations are reviewed and compared in the aspects of the error rate, latency, and capacity. Then, their performances on the frequency restoration by secondary control in the underwater microgrid are evaluated in simulations. The analytical results are dedicated to providing the future research with the innovative insights and the design guidelines.