Your 2024 Guide to Nautical Flag Etiquette

Ever wonder why there are so many boat flags? How do the sailors know which flag to put first and when? Nautical flag etiquette is an essential part of sailing. The seven most common types of boat flags are Skin Diver flags, Storm Warning flags, Coast Guard boat flags, US Jack flags, Maritime flags and Pennants, Yacht Ensign & Officer flags, and most importantly the International Code Signal flags.

Code signal flags and are frequently used by boats to send messages to other boats. They are made with a sequence of twenty-six square flags that represent a letter of the nautical alphabet. Ten numbered flags, one answering pendant, and three repeaters also form part of the nautical flag sequence.

As with most yesteryear traditions, the popularity of boat flags as a common communication tool is slowly reducing with the introduction of technology. This does not mean that we should discard this sacred tradition.

The world of nautical flags is broad, and we cannot possibly cover them all in this article. Navies, yachts and fishing boats have variations in the meaning of some flags.

While the need for nautical flags might be dwindling in the boating world, they are still pleasing to the eye. Learning when to use nautical flags and how to use them is a skill every sailor and thalassophile should have. Not only is it essential for safety reasons, but boat flags can also a lot of fun. Take a gander at our fun maritime flags and pennants!

Word of the Day: A thalassophile is someone that loves the sea!

This article will teach you the hows and whens of nautical flag etiquette. We will also provide you with a glossary of terms because, let's face it, some boating terms are pretty confusing even for a seasoned sailor.

So put your best sailor's cap on and join us on this great sea signal voyage.

What is Nautical Flag Etiquette?

As silly as it might seem, boat flag etiquette is crucial. In a worst-case scenario, it could mean the difference between life and death. Generally speaking, the nautical flag etiquette is a combination of years of maritime tradition and laws that help boats communicate messages to each other.

Different countries have varying legal requirements that should be observed for boats that enter and leave their waters or ports. So it is helpful to be mindful of sailing the vessel’s legal obligation for various countries. No one likes to pay a fine for something as simple as forgetting or putting up the wrong flag signal.

Glossary of Flag Terms

As we have stated before, the world of boating is vast and sometimes confusing. The terminology used is pretty unique. The key to understanding nautical etiquette is to know what everyone is talking about first.

Even professional sailors don't always get it right. So to help you brush up on your boating terms, we've put together this glossary with definitions. We hope this will help you to understand the nautical phrases that we will use in this article.

ABAFT- refers to the rear end or stern of a ship

AFT– means towards stern of the boat (the back of the boat)

ASTERN– it means to go towards the back of the boat

BOW- refers to the front of the ship

BUTT DIAMETER- is the width of the bottom of the flagpole.

CANTON- the rectangular part of a flag, usually at the top hoist corner of a flag, which occupies about a quarter of the total surface area of the flag

CLOSE UP- it means that the flags are now fully hoisted

COLORS- refers to the raising and taking down of the flags at 8:00 am and at sunset, respectively

COURTESY FLAG- is the national flag of the country that a boat is entering. Ex: Boats entering the United States would display an American flag as a courtesy flag.

DIP- means to lower a flag by turning it forward from an upright position to 45° or horizontal as a sign of deference or respect

ENSIGN- means a flag showing nationality of the boat, i.e. the country where the boat is registered. Ex:

  • The Red Ensign can be flown by a merchant vessel
  • The White Ensign can be flown by war or naval ships
  • The Blue Ensign can be flown by public or government vessels
  • The Civil Ensign is flown by civilian vessels
  • The Yacht Ensign is flown by yachts and is typically the largest flag on board; the flag may be flown at stern staff
  • The USPS ensign is flown by the United States Power Squadrons and is flown to signal that the boat is commanded by an active member of the USPS.

FLAG STAFF AT THE STERN- a pole at the stern/ back of the ship where the ship's country of registry flags is flown

FLY- refers to the length of the flag, measured from the heading to the fly end

GAFF- is a rig that extends from the flagpole that allows for more flags to be hoisted, which usually rises at an angle and represents the mast of a ship

HALYARD- rope or stainless steel cable used to hoist and lower flags

HOIST- the raising of flags

HOIST END- the edge of the flag that is closest to the flagpole

HOUSE FLAG- refers to the emblem that shows the company or commercial house that a merchant ship belongs to and also refers to a yacht owner's personal flag

INTERCO- stands for the International Code of Signals used in the maritime system

JACK- mean the additional national flags flown by warships (and certain other vessels) at the head of the shi

MASTHEAD- is the tallest part of a ship's mast or the lower section of a mast

NAUTICAL–refers to everything associated with maritime travel

NAUTICAL FLAGPOLE --refers to a flagpole with a yardarm and or gaff

PENNANT- is a triangular-shaped flag

PRATIQUE- refers to the license or permission to use a port from the host country

STARBOARD- is the right-hand side of the boat when you are facing the bow.

STARBOARD SPREADER- is the most forward part on the mast (if there is more than one) where the courtesy and q flags are flown

STEM– refers to the most forward part of the bow

STERN– refers to the back of the boat

STERN LINE– is the docking line that comes from the stern

TACK LINE- is the length of the halyard; it's used to separate the group of flags

UNDERWAY– means a vessel in motion

YARDARM- refers to the horizontally mounted and tapered pole attached to a flagpole to create a "t" or a cross

Flag Courtesies

Now that we are familiar with some common terminology used in nautical language, let's move on to the order in which the flags must be arranged in terms of nautical flag etiquette rules.

This order is universal across the globe. We must follow the order to avoid confusing other ships. The flag with the highest honor should be flown at the highest point.

The order is as follows:

  1. Gaff (reserved for the national ensign/ country flag)
  2. Flagstaff at the stern
  3. Bow staff
  4. Starboard yardarm (Halyard)
  5. Truck of mast (masthead)
  6. Port yardarm (Halyard)


First, we need to establish the system that governs these nautical flag rules. INTERCO is the International Code of Signals. The system is used worldwide to communicate nautical messages related to navigation, safety, and maritime.

Signal flags like the ones we are discussing in this article form part of INTERCO's signals. The other signals include radiotelegraphs or radiotelephones, ALDIS lamps, hand signals and some sound signals to name a few.

Knowing and understanding the basics of the INTERCO signaling system is extremely important for anyone interested in sailing. Whether privately or otherwise.

The National Ensign/Flag

Let's talk about nautical etiquette rules that apply for the most critical flag signal, the national ensign.

The U.S. national ensign is the preferred flag for all U.S. vessels. This ensign is also known as the “50-star of “Old Glory.” This is also the preferred ensign for yachts, especially when sailing in international or foreign waters.

Great honor is given to the national flag of the country in which the ship is registered. On the order of positioning for the flags, the national ensign is given that most senior position; the gaff. If your boat does not have a gaff, then you should fly the ensign from the flagstaff at your boat's stern.

The second rule is that you can fly no other flag above the national ensign on the same halyard. Additionally, the Jack and the National Ensign should not be hoisted together. The Jack is only hoisted when the ship is at anchor or made fast to the shore or to buoy, never when the ship is underway, when the last line is cast off, and when the anchor is aweigh. We do not recommend hoisting the Jack for recreational purposes.

The scenarios where a national ensign should be flown include:

  • When dressing the ship
  • When occupying foreign waters during the daylight hours
  • When moving along a foreign port or a combat ship (man of war)

The Courtesy Flag

Flying the courtesy flag is a centuries-old tradition that is still relevant in these modern times. The act of flying a foreign nation's flag as your ship passes through or enters its waters is not only a sign of respect, it is an essential etiquette to observe. While there is no legal requirement to fly a courtesy flag, it is a polite custom to which you should adhere.

The only legal requirement for vessels in foreign water is to fly the red ensign flag.

Where does the courtesy flag fly? As per tradition, the courtesy flag is flown at the starboard spreader. If your boat has more than one mast, you must fly the courtesy flag from the forward most mast. The courtesy flag is tied and hoisted after the authorities have granted your vessel clearance to enter their space.

Key rules for courtesy flag etiquette include:

  • Never fly the national ensign and the courtesy flag on the same mast because that will be interpreted as a sign of you are challenging the foreign nation's authority
  • Never fly a courtesy flag that is in terrible condition; this is a sign of disrespect
  • If you have guests on your boat that are of another nationality, then you should also fly their national flags as a courtesy, but never on the same mast
  • When you return to your home country, always take down the foreign country's flag

Additional courtesy flag etiquette includes:

  • If your boat is mastless, then the courtesy flag can replace any flag which is normally flown at the bow of the boat
  • If your boat has a mast with a spreader, the courtesy flag is flown at the starboard spreader

However, you must keep in mind that these rules or traditions vary from one country to another, so always make sure that you look for the correct information.

Nautical Flag Etiquette Entering a Foreign Port

The Q flag is the first flag that you must raise when entering foreign waters or a foreign port. It signals to the port authorities that your ship is healthy and you require free practice.

We always fly the Q flag in international waters before customs clears you for entry. After clearing, you then replace the Q flag with the courtesy flag. You often fly the Q flag on the starboard yardarm.

Dressing the Ship

Certain occasions require that your vessel be decked up with all the flags that it can hold. We call this dressing the ship.

It is reserved for special occasions such as public holidays or when the ship is beginning its maiden or last voyage. Dressing the ship is only done when the ship is not underway.

The ship's full splendor will be on display, so this is the time to have fun. The dressing begins at 08.00 am at anchor unless it is the ship's maiden or last voyage, then the dressing can occur at sea.

The national ensign is first. All the other flags will follow, lining up from the waterline forward to the waterline after using the stem or bowsprit end and the masthead.

We have barely scratched the surface of all the rules and customs you need to follow to observe proper nautical flag etiquette. However, we hope that we have simplified some of the most important customs in maritime tradition. Hopefully, the next time you are on a boat, you will understand the meaning of the signals and flags better. Happy sailing!

Dec 27, 2023 Joanne M

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