The size of divers-down flags displayed on vessels must be at least 20 inches by 24 inches, and a stiffener is required to keep the flag unfurled. Dive flags carried on floats may still be 12 inches by 12 inches. Also, divers-down flags on vessels must be displayed above the vessel’s highest point so that the flag's visibility is not obstructed in any direction.

Divers must make reasonable efforts to stay within 300 feet of a divers-down flag on open waters (all waterways other than rivers, inlets, or navigation channels) and within 100 feet of a flag within rivers, inlets, or navigation channels.

Vessel operators must make a reasonable effort to maintain a distance of at least 300 feet from divers-down flags on open waters and at least 100 feet from flags on rivers, inlets, or navigation channels. Vessels approaching divers-down flags closer than 300 feet in open water and 100 feet in rivers, inlets, and navigation channels must slow to idle speed.