Getting rammed by the hull or worse, the propeller of a stray boat while taking a surface dive stop is probably one of the worst nightmares for scuba divers. That’s where a Dive flag, more prominently known as a diver-down flag, arrives to save the day.
Dive flags serve as essential visual indicators informing boaters about scuba divers’ presence in the water and preventing head-on collisions. Not only that, but your dive flag also lets other boaters know better than to not call the Coast Guard on your (seemingly) abandoned dive boat!
As a cautious scuba diver, the responsibility is upon you to carry your dive flag wherever you dive.
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What Does a Diver Down Flag Look Like?
Unlike national flags, diver-down flags are usually square shaped, and as per the latest standard, the base of the flag must be bright red with a white stripe running diagonally from left to right. Red is the color with the highest visibility in the color spectrum and white offers the ideal contrast. So, this color combination can be easily spotted in the blue waters from large distances by other vessels and boats.
Although not mandated by law, according to DAN dive flag safety guidelines the standard dimensions of the flag should ideally be at least 12 x 12 inches when placed on a buoy and 20 x 24 inches, when towed to a boat. The diagonal stripe thickness is expected to be 1/3rd or 1/5th the side length.
If you are buying a complete dive flag set the flag comes with a detachable rod to hoist the flag on, along with an inflatable float (often called a buoy) on which you can place the rod.

What Are Dive Flags Made Of?
Prolonged saltwater exposure can weaken standard silk material. Hence dive flags are made with durable nylon or polyester fibers.
What Are the Two Types of Diver Down Flags?
While a white diagonally striped flag on a red backdrop is internationally recognized as the standard color scheme of scuba flags, there is another flag known as the alpha flag (sometimes called the alfa flag) with a different color combination that serves the same purpose as a diver-down flag.
The alfa flag features a blue and white colored piece of fabric with a swallow-tailed incision on the blue end. Technically speaking, although alfa flags are sometimes used by scuba divers as a dive flag the original purpose of the alfa flag is not quite the same as the red and white diver-down flag but there is a significant overlap between their intent.
As for the reason behind the emergence of two dive flags, there’s a long history of ownership rights feud. You may want to check out this detailed resource on the history of dive flags at the scuba board forum.
How Is the Alfa Flag Different from the Diver-Down Flag?
When a boat operator spots a standard red diver-down flag, it generally implies “There’s a diver within 100 meters of the flag(and dive vessel), please exercise caution while sailing around.“
The presence of an alfa flag, on the other hand, has a broader implication- “The vessel in the vicinity of this flag is engaged in underwater operations or is inoperable. Please maintain distance and exercise caution.” Underwater operations can mean a lot of things apart from scuba diving. The alfa flag is generally used by research vessels and divers.
As a scuba diver, you can use any of the flags as they essentially serve the same purpose for you. Although, the color red being more flashy, is a better option to catch the eye of boaters from a distance.
To Tow or Not to Tow
Ah, the excellent diving dilemma: to tow or not to tow your dive flag? It’s a question that plagues many dive safety regulation nerds in the scuba diving community. So, what exactly is towing?
It means that instead of tying the loose end of your flag buoy’s reel to the end of your boat, you have to tow (drag) it along with you.
Towing your dive flag along makes your immediate underwater location more at par with the surface position of your dive flag to boat operators and your dive buddies on the surface.
But let’s not overlook the flip side of the coin. Dragging your dive flag along can greatly hamper your underwater mobility. The flag rope creates extra drag, affecting your buoyancy and overall maneuverability, not to mention the constant struggle to maintain the tension on the rope to prevent getting yourself entangled underwater. Yikes!
Now, let’s address the naysayers who argue against towing a dive flag. They claim it’s unnecessary, that relying on boat operators to steer clear of the dive flag area is sufficient. While it’s true that responsible boaters should keep an eye out for divers, would you trust your life to some random boater in the middle of the ocean? YOU BETTER NOT.
If your dive involves drifting away more than 50 meters from your dive boat or in inlets or channels with frequent passage of boats, towing the flag along with you is a good safety measure. Otherwise, you can simply tie your dive flag to your anchored dive boat and go on about your underwater business.
How Close Should You Stay to the Dive Flag?
As a diver, your safety is in your hands. If you can tow your dive flag along with you, that’s what I would recommend. Otherwise, don’t stray away from your dive flag too much.
DAN recommends that you stay within a distance of 300 feet (90 meters) from your dive flag or surface buoy in open water and 100 feet (30 meters) when diving in rivers, inlets, or navigation channels.
These are the upper limits of safe distance from the dive flag so keeping that in mind, try to stay within this limit. The sweet spot is around 100 feet (that’s 30 meters) from the flag. Make a conscious effort to surface within 50-80 feet of the dive flag.
Boaters, Give The Divers Space
If you are a boat owner or operator, make sure to give a wide berth to any diver-down flags you encounter. Be a responsible vessel operator and keep your eyes peeled for any signs of dive flags or surface buoys.
When operating a non-diving-related vessel in areas known for frequent dive activities, if you spot a dive flag the minimum recommended distance you should maintain from it is 150-200 feet (45-60 meters).
Stay Visible, Stay Safe
In the end, remember the golden rule: respect the dive flag and maintain a safe distance. For divers, stay as close as possible to your dive flag. Boaters, on the other hand, stay as far as you can. So, next time you’re out there, keep your eyes on the flag.
Dive with caution, boat with care, and let’s make every water escapade an unforgettable, yet secure journey. Stay flag-tastic, water explorers!