Abstract: A multi-modal communication system and method capable of operating underwater, at an interface such as the surface of water, and in the atmosphere using a plurality of communication modes including optical, acoustic, and radio frequency communication. The nodes include underwater vehicles, divers, buoys, aerial vehicles, and shore-based operators. In one aspect, the system and method are capable of high-speed optical and long-range acoustic communication through transitioning between communication modes dependent upon signal conditions. It is another aspect to provide a system and method designed for clandestine operation that is not easily detected when in use.