Abstract: An underwater communication method, device, and system that enables bi-directional communication between and among under-water divers. In accordance with the present invention, messages may be transmitted and received between and among the divers in a network and/or between divers and a diving boat, buoy, or other reference point. The present invention also permits one or more divers to receive a homing signal and to move toward the source of that signal using an acquisition and tracking feature and functionality that utilizes a Doppler frequency shift and preferably a compass to determine the distance and direction of the source of the signal. The present invention also enables a diver in distress to broadcast a distress signal (i.e., SOS) that is received by every other diver within a predetermined distance from the distressed diver. The divers receiving the distress signal are then able to locate and rescue the distressed diver using the acquisition and tracking feature and functionality.