International Code of Signals flags, A to Z

The 26 letter flags with their phonetic names and single-letter meanings. Learn them here, then test yourself against the kraken.

Play the flag game

The flag locker

One flag, one message. Explore the 26 letter flags and their single-letter meanings before your next voyage.

A · Alfa

I have a diver down; keep well clear at slow speed.

B · Bravo

I am taking in, or discharging, or carrying dangerous goods.

C · Charlie

Yes (affirmative, or the preceding group should be read in the affirmative).

D · Delta

Keep clear of me; I am maneuvering with difficulty.

E · Echo

I am altering my course to starboard.

F · Foxtrot

I am disabled; communicate with me.

G · Golf

I require a pilot. For fishing vessels close together on fishing grounds: I am hauling nets.

H · Hotel

I have a pilot on board.

I · India

I am altering my course to port.

J · Juliett

I am on fire and have dangerous cargo on board; keep well clear of me, or I am leaking dangerous cargo.

K · Kilo

I wish to communicate with you.

L · Lima

You should stop your vessel instantly.

M · Mike

My vessel is stopped and making no way through the water.

N · November

No (negative, or the preceding group should be read in the negative). Visual or sound only; use “NO” by voice or radio.

O · Oscar

Man overboard.

P · Papa

In harbor: All persons should report on board as the vessel is about to proceed to sea. At sea, for fishing vessels: My nets have come fast upon an obstruction. As a sound signal: I require a pilot.

Q · Quebec

My vessel is healthy and I request free pratique.

R · Romeo

No single-letter meaning is assigned in the International Code of Signals.

S · Sierra

I am operating astern propulsion.

T · Tango

Keep clear of me; I am engaged in pair trawling.

U · Uniform

You are running into danger.

V · Victor

I require assistance.

W · Whiskey

I require medical assistance.

X · X-ray

Stop carrying out your intentions and watch for my signals.

Y · Yankee

I am dragging my anchor.

Z · Zulu

I require a tug. For fishing vessels close together on fishing grounds: I am shooting nets.

Signal flags study certificate

30 questions, 25 minutes, 80% to pass. Flags are shown as drawings; sign in to receive the study certificate.

Take the exam

CIS FIGHTER · SIGNAL CHALLENGE

CIS Fighter

Know the flag. Save your ship. Take on the kraken and learn the 26 flags of the International Code of Signals.

Play the flag game

From the International Code of Signals

Single-letter meanings for study. Context matters: fishing vessels and vessels in port can use some flags differently. For navigation, consult the complete official code.

Reviewed September 9, 2026