Abstract: A simple visible light communication method and system that, underwater in an ordinary water-quality in which a diver is allowed to go under the water, are able to reliably communicate with a ship, or the like, above water while the diver is stopping at a safety stop position at a depth of 5 m in order to prevent occurrence of dysbarism. The visible light communication method and system us the visible light communication system that includes a transmitter and a receiver and that is usable underwater, and include at a transmitting side, modulating information to be transmitted to pseudo-white light that is adjusted to have a color temperature of 4000 to 10000K and a luminous flux of 550 to 1500 lumens and that is emitted from an LED, and transmitting the pseudo-white light; and, at a receiving side, extracting the information by demodulating the received pseudo-white light.