A **courtesy flag** is a small national flag flown by a visiting foreign vessel from the starboard yardarm or foremast to indicate respect for the host country. The courtesy flag is flown on entering the host’s territorial waters and lowered on leaving them. It is flown below the host country’s quarantine flag when the latter is also required, and is treated with full national honours.
**Example**: A yacht arriving in French waters flies the French tricolore as a courtesy flag at the starboard spreader.
**See also**: [q-flag](/glossary/q-flag/), [ensign](/glossary/ensign/), [ensign-at-sea](/glossary/ensign-at-sea/), [signal-flag](/glossary/signal-flag/)