Dive flags should be displayed on a boat or surface support station whenever divers are in the water. This alerts boats that divers are in the area. The two flags used by divers are the United States dive flag and international diver code "Alpha" flag.

The United States dive flag is used by most recreational divers in the United States. Displaying this flag tells boats to stay clear of the area because divers are in the water. Local laws determine the exact distance boats must keep from the flag, but this is usually 100 feet.

The international diver code "Alpha" flag is displayed by most dive boats. This flag states that the boat's movement is restricted because divers are in the water.

No matter which flag is displayed, it should be removed as soon as divers exit the water.