All About Dive Flags

The Different Types of Dive Flags and When to Use Them

Most divers are familiar with the iconic red and white "diver in the water" dive flag -- it can be found printed on scuba diving shirts, bumper stickers, log books and other diving paraphernalia. For many divers, the image of the diver flag is a way to advertise their love of diving, but dive flags also fulfill a practical purpose.

What Is the Purpose of Flying a Dive Flag?

red and white dive flag
A diver down flag in use. ©

Dive flags are used to alert boats and other watercraft that divers are in the area, possibly near the surface. Flying a dive flag should prevent accidental collisions between watercraft and ascending scuba divers. Some commercially available dive flags are attached to floating surface support stations, such as an inflatable buoy or inner-tube, which can be used as a floatation device and temporarily hold dive gear. Dive flags also help surface support personnel track the location of submerged divers.

What Do Dive Flags Look Like?

The recreational diving industry recognizes two flags: the white-on-red striped flag and the alpha flag. They have different applications, and the recommended (sometimes required) use of dive flags varies with location. Familiarize yourself with local diving regulations regarding dive flags before diving in a new location.

The Red Diver Flag

scuba diving flag used to warn of divers in the water
the diver down red and white scuba flag. wikipedia commons

The diver-in-the-water flag is the well-known red flag bisected by a white, diagonal stripe. The stripe runs from the upper left corner of the flag to the lower right corner. This flag is used when divers are in the water to alert boats to the possibility of divers near the surface. In most locations, these flags should be lowered or removed from the water after the divers have safely exited the water. Legislation in many parts of North America requires that diver flags be flown whenever divers are in the water, and the flag is recognized in most parts of the world.

The Alpha Flag

blue and white dive flag
the alpha flag used in scuba diving to warn of boat immobility. wikipedia commons

The alpha flag is a white and blue flag with a triangular notch on the free end. The left side of the flag is white and the right side of the flag is blue. The alpha flag is recognized internationally and serves a different purpose from the red-and-white flag. The alpha flag is flown by a boat whenever the mobility of the vessel is restricted. Other watercraft should recognize that the boat can not move quickly, and should yield the right-of-way to a vessel flying an alpha flag.

A dive boat must stay close to the divers it is tending, so it cannot easily move from the vicinity of the people under the water. In many parts of the world, the alpha flag is recognized as an indication that divers are in the area, but the flag has multiple uses and it is advisable to fly both the alpha flag and the diver-in-the-water flag to avoid confusion.

When Should You Fly a Dive Flag?

diver down flag
A dive boat flies a red and white diver down flag from the mast. wikipedia commons

Dive flags must be raised whenever there is the possibility of boat traffic at or near a dive site. Dive boats usually display both the diver flag and the alpha flag in North America. When diving from a boat, a dive team need not carry its own dive flag provided that it stays within a predefined proximity of the dive boat.

When shore diving at sites where watercraft traffic is a possibility, divers should float their own dive flag on the surface, and stay within a few hundred feet of the flag. The exact distance varies with location, but most North American dive regulations require that divers stay within 50 to 300 feet of the dive flag, depending upon the dive site.

How Close Can Boats Get to Your Dive Flag?

Boats and other watercraft should stay well clear of dive flags should decrease their speed when approaching an area where a flag is visible. The exact distance varies with location -- usually between 50 to 300 feet of the dive flag.

How Should a Diver Carry a Dive Flag?

a dive flag float
A scuba diver exits the water carrying a dive flag and float. ©

In situations that require a diver to fly his own dive flag, the diver should tow the dive flag above him during the dive. Commercially available dive flags usually come with a buoy or inflatable raft to keep the flag upright at the surface. The diver tows the flag using a line attached to a reel. The reel should contain a length of line several times longer than the anticipated depth of the dive.

Never clip the reel to your buoyancy compensator or dive gear when it is attached to a dive flag because you risk becoming entangled in the line or dragged along behind a flag snagged by a boat. Divers who are using a dive flag should also carry a line-cutting device to cut the line in case of entanglement. Finally, all dive flags should be stiff enough to remain unfurled and visible without the wind.

What Should You Do If You Have to Surface Far From Your Dive Flag?

a diver and a safety sausage
A diver displays a surface marker buoy. ©

In an ideal world, divers would always surface just underneath their dive flags or very close to the dive boat. However, it is possible that a diver may become disoriented or have an emergency, and have to surface away from the dive flag. For this reason, it is a good idea to carry an inflatable surface marker buoy at any dive site where there is the possibility of boat traffic. The buoy should be attached to a reel and should be inflated and sent to the surface before the diver attempts to surface. A diver surfacing far from his dive flag or boat should always scan the surface of the water and listen for boat traffic before surfacing.

Flags Protect Diver Safety!

Dive flags alert boat traffic to the presence of divers in order to avoid a collision. A diver should take care to surface near his dive flag or dive boat anytime there is the possibility of boat traffic. However, not all boaters are familiar with the use of dive flags, or aware enough to notice their presence. Before surfacing, divers should always look and listen to confirm that no boats are passing overhead.

  • Why Are Safety Stops Important?
  • Flying After Diving

Safety First!

The white-on-red scuba flag is a cultural artifact, but it's also an essential piece of survival gear for any diver. If you're on the water and see a diver flag, give that area a wide berth.