What Are the Different Types of Diving Flags and What Do They Mean?

November 20, 2022

In Canada, diving usually takes place during the summer, when the water is warmer and favours the discovery of local aquatic wildlife. Unfortunately, this delightful activity can also be a dangerous one, particularly because divers are usually sharing the waterways with plenty of boaters. To minimize the risk of accidents, Transport Canada has implemented regulations requiring the use of diving flags.

Here’s everything you need to know about dive flags to help keep yourself safe in the water.


What is a diving flag?

A diving flag an important piece of boating safety equipment to have on board your vessel. These flags help ensure the safety of divers, spearfishers and freedivers in the water.

The purpose of a diving flag is to indicate to pleasure boaters that divers are under the water nearby. With this information, boat captains can adjust their speed accordingly to keep the divers safe.


What do diving flags mean?

Like marine buoys and markers, diving flags have specific colours and meanings that all divers and boaters should know before getting out on the water.


The Alfa/Alpha flag

According to the International Code of Signals, the Alfa or Alpha flag is used to indicate divers down. More specifically, the blue and white flag indicates the presence of divers within 100 m of the vessel flying it. It also emphasizes the fact that the vessel in question has reduced maneuverability.

The Alpha flag signals nearby vessels to avoid the diving area. Boaters who see this flag should keep a safe distance and reduce their speed to avoid disturbing the divers. The Alpha flag must be rigid and placed at least 0.5 m up on the mast so that it is easily visible from a distance. Depending on visibility and other factors, it may be displayed alongside the red diver-down flag.




The diver-down flag

The diver-down flag is red with a white diagonal stripe and is also used to indicate the presence of divers in the water. This flag is displayed on boats at anchor or on buoys in the diving zone, and is mainly used in North America.




The red diving flag with St. Andrew’s Cross

Less commonly used than the two diving flags discussed above, the St. Andrew’s Cross diving flag can be found on stationary vessels and generally signals the presence of freedivers or spearfishers. The safety rules for this flag are the same as those associated with the Alpha flag.



When to use diving flags

Diving flags should be used whenever diving activities are taking place, regardless of the type of waterway in question. These flags indicate the presence of divers to other boats so that they can keep their distance and make the area safer for the divers. Reboarding devices can then be used more safely.


Learn more about diving flags from the National Boating Safety School

Diving flags are one of the basics of boating. It’s important to know how to recognize and use them in order to ensure your safety and that of others.

The National Boating Safety School offers a Transport Canada approved boating safety course to help individuals prepare for the boating exam to obtain their Canadian boat license. Register today to learn everything you need to know about marine navigation signals and more!

Get your card today