What do NATO navy flags mean?

Watch Chief Petty Officer Alexander, the Chief Yeoman on board the German Navy frigate FGS Bayern explain how Allies still use signal flags to communicate with each other.

According to NATO:

Signal flags are colourful and eye-catching, but do you know what they mean? These flags are not just for decoration; they are still a vital way of sending messages across the seas. Each flag represents either letters or numbers that can be used together to form words or codes, or has a specific standalone meaning. By combining them in different ways, ships can communicate with each other, and with their surroundings in a snap.

Signal flags have a long and rich history that dates back to the 18th century when they were first used by naval and merchant vessels. Today, they are still used by NATO navies, especially in situations where radio communication is not possible, reliable or secure. Signal flags are not only a practical tool, but also a symbol of maritime culture and tradition.