While Boating, See a Red Flag With a White Diagonal Stripe | What This Means?

Fact Checked By James A Rockey | Post Updated On: December 10, 2022
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A red flag with a white diagonal stripe is known as a diver-down flag. If you see this type of flag on the water then it means a diver is in the water and you have to drive your boat carefully.

Key Takeaways

  • If there is a diver on the water then the diver-down flag should be hoisted on the vessel or on a floating buoy from where it can be easily spotted by other kayakers or boat drivers
  • The diver-down flag was created in 1956 by Denzel James Dockery and Ted Nixon of US Divers made it popular all over the USA
  • The limit of diving is around 90 meters from the flag so if you are driving a boat then you must not drive the boat inside 90 meters

What is a diver down the flag (or a Red Flag With White Diagonal Stripe)?

While boating or kayaking, you may see a red flag with a white diagonal stripe and may wonder what this flag means. The flag is known as a diver-down flag. It allows other kayakers and divers or boat drivers to know that the divers (sometimes Scuba Divers) are in the water. 

This flag should always be hoisted on a vessel, kayak, or on floating buoy from where it can be easily spotted by other divers, kayakers, and boat drivers. The white diagonal line is made of reflective material so that it can be easily visible at night.

This Diagonal Striped Flag was created in 1956 by Denzel James Dockery and Ted Nixon of US Divers made it popular all over the USA

The limit of diving is around 90 meters of the Flag so that other vessel owners can take it for granted where to go and where’s not with their boat. 

Guidelines for the divers and kayakers

Diving, kayaking, or while performing any adventurous water sport, safety comes first. Anything can happen at any time, and therefore, most water sports associations come up with various guidelines to keep divers safe from any danger and imminent accidents.

Here are some rules to follow:

  1. Always enter the water after the boat engine is shut down or, else the chances of getting hurt become high. It’s better to have communication with the people on board and the group of people who are kayaking.
  2. Make proper evacuation and emergency plans in case of any injury or accident. Read the procedures properly and make an action plan accordingly. Also, it is advised to be vigilant at all times to keep an eye out.
  3. Always take the help of diver down flags in case of injury or any other emergency so that one can be visible to the boaters and other help to come your way.
  4. Avoid having alcohol before going for kayaking or diving. You will violate the Florida law if your breath-alcohol level is over .02 and your blood alcohol level of .08. Source – Texas Parks & Wildlife Department. According to the Texas TPWD – Alcohol plays a major role in 50% of all boating accidents. 

Guidelines for the Drivers of Boats (Boaters)

There are many boating safety guidelines and rules available to follow if you are driving your boat or kayak. These rules make sure that the kayakers and divers around the vicinity of the boat remain safe.

Here are some guidelines to follow:

`1. The first and foremost guideline for a driver is to look for other drivers in the water to avoid any kind of accident.

2. Make sure you have all kinds of equipment and supplies (Life Jacket) on the boat for any first aid situation or for helping divers using the communication system or oxygen units. Switch off the engine around the diver’s area so that any accident because of the propeller can be avoided.

3. Look for diver down flags in the water and try to look carefully because many times, the divers may not be visible due to glare, waves, or, weather conditions.

4. The owner or the operator of a boat/vessel must store or carry some safety equipment regulated by US Coast Guard (USCG). 

What To Do If You See Such a Red Flag With a Diagonal Stripe While Boating?

As a boat driver or vessel owner; you must know the meaning of it and how important it is for the safety of all the people around on the water. Here are some tips to follow – 

  1. Don’t hesitate to keep your boat far away (at least 300 feet (ca. 91 m)) from the flat. There is no place to assume or doubt. Just stay away from the flat to stay safe or hurt anyone. 
  2. While driving the boat, if you are experienced in the location – you may know where people often come for diving. Just stay slow in those locations. Because, you know — we are human and do mistakes and break the law all the time (so don’t expect the flag all the time, it’s a serious breach of law though).
  3. Try to communicate if anyone accidentally becomes closer to your boat. Let them know you are coming and alert them to stay far away. But you should always look up at people as you are on the boat and clearly see them around. 
  4. Just before starting your boat, double-check the back of your boat that nobody is near or under your propeller. 
  5. Always make sure you have all the necessary first aid kit and oxygen and other fundamental safety tools stored on your boat. Because you never know when an accident takes place. 
  6. Besides that Red Alpha Flag, always look for SMB or DSMB (Surface Marker Buoy) because divers may use that as well instead of the traditional mariner red flag. 


  • https://www.tcpalm.com/story/sports/2018/07/12/boating-tip-dive-flags-out/778243002/
  • https://boatingscout.com/red-flag-with-a-white-diagonal-stripe-while-boating
  • https://www.boat-ed.com/arkansas/studyGuide/Diver-Down-Flags/10100302_27424/

James A Rockey

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