Persons scuba diving, skin diving, or snorkeling must display a diver-down flag to mark their diving area. If a diver-down flag is spotted while boating, be careful and do not approach out of curiosity.
- Maintain a distance of at least 100 feet between the flag and your vessel when boating on inland waters.
- In bays and open waters, stay at least 300 feet away.
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.
Two types of flags are used to indicate diving activity.
Divers Flag: A rectangular red flag with a white diagonal stripe is attached to a vessel, float, or buoy.
Alfa Flag: A blue-and-white International Code Flag A (or Alfa flag), at least 3.3 feet (one meter) high and visible from all directions, must be displayed on vessels on federally controlled waters. This flag indicates that the vessel is involved in a diving activity.