What Is The Flag On A Boat Called? | LakeWizard

Key Takeaways

  • Boat flags have lots of different names, depending on what information they are meant to convey.
  • The most important flag is the national ensign which shows the nationality of a given boat.
  • Boat flags can also be used to denote military rank, company ownership, or show respect.
  • Boat flags can also be used to send signals between vessels.
  • The rules surrounding boat flags are strictly enforced and regulated internationally.

If you’ve ever seen a boat before, chances are you’ve noticed the many flags that often adorn them, but what is a flag on a boat called?

The flag you see on a boat is called an ensign. An Ensign is an international flag that indicates where the vessel is from. It is usually the largest flag on a ship and is most commonly flown at the stern or  back of a boat.

Flags are very important in the world of boating and they are used for a variety of different purposes including identifying a ship and signaling crew members on other ships. However, there are tons of different maritime flags used today and ensigns only make up a small portion of all the different flags that are used on a regular basis. So what are these different flags called and what are they used for?

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What Is The Flag On A Boat Called?

There isn’t one single name for a flag on a boat as there are lots of different kinds of nautical flags that are used for a variety of different purposes. Nautical flags have been incredibly important since people first started venturing out onto the high seas and rules, regulations and general flag etiquette are strictly enforced all over the world.

Because these flags serve so many different purposes, nautical flags come in all different shapes, sizes, and colors, with both triangular and rectangular flags being the most common. Most boats have two flags or more.


The most common and important of all nautical flags on any vessel is the ensign. Being that ensigns are normally just the national flags of whatever country the ship is registered to, they are usually the largest flag flown on a vessel. They are traditionally flown at the back, or stern of the ship.

There are multiple different types of ensigns that convey additional information however, all ensigns display the nationality of the vessel they’re flying on.

For example, a civil or national ensign can be flown by any ship registered to that country, however, naval ensigns can be flown by navy ships to convey that they are part of the navy, and yachts or other recreational boats may fly a yacht ensign.

Still, no matter what, every ensign flag coveys the nationality of the ship, but different types like yacht and naval ensigns also convey additional information.


In addition to the national ensign, certain ships may also fly a jack flag, which is simply another national flag. The big difference between a jack and an ensign is that, instead of being flown at the stern of the ship, a jack is flown at the front, or bow of the ship on the appropriately named jackstaff.

Jacks are usually rectangular, or often square in design, though they are usually much smaller than the national ensign flown at the stern of a ship.

Not every boat is allowed to fly a jack, with most countries only allowing naval vessels to fly them. The jack’s usage also varies by country with many countries having different jacks to fulfill different purposes, with some being used on special occasions

The most famous of these jack flags is the Union Jack which was originally created for naval purposes but now serves as the de facto national flag of Great Britain.

Rank Flag

Rank flags are worn only by superior officers on naval and coast guard ships and, as the name implies they show the rank of the superior officer.. Though made obsolete with modern communication technology, these flags have their origin in a time when orders between ships needed to be given via flag signals, and they essentially showed which ship should be watched for orders.

For this reason, even today, if there is a group of naval vessels that has more than one superior officer onboard, only the highest ranking officer or the person in command is allowed to wear their rank flag.

In the US Navy, the rank flags flown by admirals are rectangular with stars that denote rank. These flags can either be blue with white stars or white with blue stars depending on the type of officer.


Pennants differ from all of the aforementioned flags, as these flags are long narrow, and triangular in shape and can also be used for a variety of different purposes.

One of the most common types of pennants is the commissioning pennant. These flags are flown from the main masthead from the time that the ship enters service until the ship is retired.

Church pennants are also flown by some but all navies around the world when some sort of religious service is taking place on board and a gin pennant can be used to invite all of the naval officers from ships in company to the wardroom for drinks.

House Flag

House flags aren’t the most common flags in the world however, there are still lots of boats that fly them. These flags are flown by merchant ships or other commercial vessels to show which company they are owned by, and are usually flown on the jackstaff at the bow of a ship.

Yacht Club Burgees

A Burgee is usually a triangle-shaped distinguishing flag that can be used to show that the owner and his boat are part of some sort of recreational boat organization, including yacht clubs. If you are a yacht owner and you are part of a yacht club, you can fly your yacht club burgee to show where your loyalties lie.

Remember this is different from a yacht ensign, which shows the national flag of the country where a boat is registered and not the club affiliation.

Signal Flags

Flags can also be used to send signals to other vessels and, in fact, there is a well established and internationally recognized system called the International Code of Signals that allows sailors to do exactly that.

These signal flags come in a lot of different shapes are sizes and they have a variety of different meanings, including “I require medical assistance” and “Man overboard.”  These signal flags also have letters associated with them so that they can be put together with other letters to spell out messages to other boats.

Outside of this international system, personal flags can also be used to send private signals between vessels.

Courtesy Flag

A courtesy flag is different from other flags in that it is only flown in foreign waters and mostly has to do with flag etiquette. If a ship, particularly a naval ship, is traveling through foreign waters, the senior officer may choose to display the national maritime flag of the country the boat is in.