Scuba divers or snorkelers must display a diver-down flag that marks their diving area. The person(s) diving must stay within 100 feet of the vertical position of their diver-down flag. Vessels must remain at least 200 feet away from a diver-down flag.
Two types of flags are used to indicate diving activity.
Scuba divers and snorkelers should not place a flag in an area already occupied by other boaters or where their diving operation will impede the normal flow of waterway traffic. Divers also should follow all of the water safety rules themselves.