Dive Flag

A dive flag is a vital safety device used in recreational and professional scuba diving to indicate the presence of divers in the water. Its primary purpose is to alert nearby boaters and other watercraft of the presence of divers, reducing the risk of collision or injury. Dive flags are also utilized to signal to other divers that a dive is in progress, helping maintain separation and avoid confusion in busy dive areas. There are two internationally recognized dive flags: the red rectangular flag with a white diagonal stripe, known as the Alpha flag, and the blue and white double-tailed pennant, referred to as the Diver Down flag.


Dive flags have been a part of scuba diving safety protocols since the early days of the sport. The red and white Alpha flag was first adopted by the International Maritime Organization (IMO) in 1961 as part of the International Code of Signals, which standardizes nautical communication. The blue and white Diver Down flag, meanwhile, was developed in the United States during the 1950s and has since become popular around the world.

Design and Specifications

  1. Alpha Flag

The Alpha flag is a red rectangle with a white diagonal stripe running from the top left corner to the bottom right corner. It is often referred to as the “A flag” or “Alfa flag,” as it represents the letter “A” in the NATO phonetic alphabet. The dimensions of the flag can vary, but the width-to-length ratio is typically 1:2. The flag must be clearly visible from all directions and be of a size appropriate for the vessel or dive site.

  1. Diver Down Flag

The Diver Down flag, also known as the “B flag,” consists of a blue field with a white, double-tailed pennant at its center. The flag’s dimensions can vary, but the width-to-length ratio is usually 3:5. The flag should be clearly visible from all directions and be of a size appropriate for the vessel or dive site.

Usage and Regulations

Dive flags are used to mark the location of divers in the water, either by being displayed on a dive boat or by being attached to a surface float. When flying a dive flag, it is crucial to ensure that it is securely fastened and visible from all angles. Divers should also maintain a safe distance from the flag to prevent entanglement or injury.

Dive flag regulations vary depending on the jurisdiction. In many countries, it is mandatory to display a dive flag when conducting diving activities. Boaters are required to maintain a safe distance from dive flags, typically 50 to 100 meters, depending on local regulations. Additionally, divers are often required to surface within a certain distance of the dive flag, which can range from 15 to 50 meters.

In the United States, the use of dive flags is regulated by both federal and state authorities. The U.S. Coast Guard mandates the use of the Alpha flag on vessels engaged in diving operations, while the Diver Down flag is more commonly used by recreational divers. State regulations may differ in terms of size, visibility, and distance requirements.

International Recognition

While the Alpha flag is recognized internationally, the Diver Down flag is predominantly used in the United States, Canada, and the Caribbean. Some countries may not officially recognize the Diver Down flag, but it is generally accepted as a courtesy among the diving community. Divers traveling to other countries should familiarize themselves with local regulations and the appropriate dive flag to use.

Safety Tips

When using a dive flag, divers and boat operators should follow these safety tips:

  1. Ensure the dive flag is clearly visible from all directions and of appropriate size for the vessel or dive site.
  2. Maintain a safe distance between the flag and divers to prevent entanglement or injury. 3. Boaters should remain vigilant and maintain a safe distance from dive flags, as specified by local regulations.
  1. Divers should surface within the designated distance of the dive flag, as required by local regulations.
  2. Regularly inspect dive flags for wear and tear, replacing them when necessary to ensure optimal visibility.
  3. When diving in unfamiliar locations, research local dive flag regulations and follow them accordingly.
  4. In the absence of a dive flag, divers should use other means to signal their presence, such as a surface marker buoy (SMB) or a delayed surface marker buoy (DSMB).
  5. Always have a dive plan in place and communicate it with your dive buddy or the dive group.
  6. Dive flags should not be used as a substitute for proper dive planning and situational awareness.


Dive flags play a crucial role in promoting safety during scuba diving activities by alerting others to the presence of divers in the water. Both the Alpha flag and the Diver Down flag serve as essential tools for maintaining visibility and preventing accidents. By adhering to local regulations, using the appropriate flag, and following safety tips, divers and boaters can ensure a safer diving environment for everyone involved.