Submarine communication refers to the methods used to transmit information underwater. Traditional radio waves do not travel well through water, especially at greater depths. Instead, submarines often use sonar systems, which send sound waves to communicate with other vessels or to detect objects in the water. Another method involves the use of underwater cables, which are laid on the ocean floor to carry signals over long distances. These cables can transmit data quickly and reliably, connecting different parts of the world. Both methods are essential for military operations and global communication networks.