Sailing · Maritime signals

The nautical flag alphabet

The International Code of Signals flags from A to Z: what each looks like, what it is called and what it means when it flies alone.

Each flag stands for a letter, and on its own it also sends a message. Spell any word in flags, with the meaning of each one, in Phonetic Relay.

Spell a word in signal flags →

The nautical flag alphabet, A to Z

Letter	Name	Meaning on its own
A	Alpha	I have a diver down; keep well clear at slow speed.
B	Bravo	I am carrying or handling dangerous goods.
C	Charlie	Yes.
D	Delta	Keep clear of me; I am having trouble steering.
E	Echo	I am turning to starboard (right).
F	Foxtrot	I am disabled; talk to me.
G	Golf	I need a pilot.
H	Hotel	I have a pilot on board.
I	India	I am turning to port (left).
J	Juliet	I am on fire and carrying dangerous cargo; keep well clear.
K	Kilo	I want to talk to you.
L	Lima	Stop your boat at once.
M	Mike	My boat is stopped and going nowhere.
N	November	No.
O	Oscar	Man overboard.
P	Papa	Everybody come aboard; the boat is about to sail.
Q	Quebec	My boat is healthy; I ask to be let into port.
R	Romeo	No meaning on its own today. It once meant: my boat has stopped, come past.
S	Sierra	My engines are running astern (backwards).
T	Tango	Keep clear of me; I am trawling in a pair.
U	Uniform	You are heading into danger.
V	Victor	I need help.
W	Whiskey	I need a doctor.
X	X-ray	Stop what you are doing and watch for my signals.
Y	Yankee	My anchor is dragging.
Z	Zulu	I need a tug.

How the flags are used

One flag sends the urgent, common messages above: O for man overboard, V for “I need help”, W for “I need a doctor”.
Two or more flags flown together form codes from the International Code of Signals, read from the top down.
Dressing a ship with a line of flags from bow to stern is decoration on special days, not a message.

The flags are named with the NATO phonetic alphabet, and a ship can send the same letters by light in Morse code.

Questions

What are nautical flags?

They are the International Code of Signals flags that ships use to talk to each other without radio. There is one flag for each letter, and each flag flown on its own also has a meaning, such as O for man overboard.

What is each flag called?

By the NATO word for its letter: the A flag is Alfa, the B flag is Bravo, and so on. That is why sailors learn the flags and the phonetic alphabet together.

What does the blue and white flag mean?

The swallow-tailed white and blue flag is Alfa: “I have a diver down; keep well clear at slow speed”. In the US, recreational divers also use a separate red flag with a white diagonal stripe.

Can I spell my name in signal flags?

Yes. Type it into Phonetic Relay in signal flag mode and you get the flags in order, each with its meaning.

Are there flags for numbers?

Yes. The full code has ten numeral pennants and three substitute flags as well. This page shows the 26 letter flags.