When cruising in foreign waters, flying a courtesy flag is a key part of maritime etiquette and, in some cases, a legal requirement. Here’s what you need to know about it:

What is a Courtesy Flag?

A courtesy flag is a small version of the national flag of the country whose waters you are sailing in. It is flown as a gesture of respect to that nation.

Where and How to Fly It

• Starboard Spreader of the Mast (For sailboats): The courtesy flag is traditionally hoisted on the starboard spreader of the mast, below any quarantine or signal flags.
• Starboard Yardarm or a Halyard (For powerboats): On boats without a mast, the flag is flown from a prominent location on the starboard side.
• After Clearing Customs: The flag should only be hoisted after you have officially cleared customs and immigration.
• Replacing the “Q” Flag: If you arrive in a country and haven’t yet cleared customs, you must first fly the yellow quarantine flag (“Q” flag). Once customs clearance is completed, you replace the “Q” flag with the courtesy flag.

Size and Condition

• The flag should be proportionate to your boat’s size (about 1 inch of flag length per foot of boat length is a common guideline).
• It should be in good condition—tattered or faded flags are seen as disrespectful.

Flags You Should NOT Fly

• Never fly a foreign courtesy flag higher than your home country’s flag.
• Avoid flying an old or incorrect version of a country’s flag.
• Some countries prohibit flying their naval or government flags as a courtesy flag (e.g., the UK’s White Ensign).

Do All Countries Require a Courtesy Flag?

While not all nations legally require it, most experienced sailors do it as a sign of goodwill. Some places, like France and Spain, are known for being more strict about courtesy flags, and officials may reprimand or fine boats that do not comply.

Read more about other bureaucratic necessities.