The Hydrophiinae, also known as coral reef snakes or sea snakes, are a subfamily of venomous elapid snakes that inhabit marine environments for most or all of their lives. Most are extensively adapted to a fully aquatic life and are unable to move on land, except for the genus Laticauda, which has limited land movement. They are found in warm coastal waters from the Indian Ocean to the Pacific and are closely related to venomous terrestrial snakes in Australia.