
International Signal Flag
and Pennant Alphabet
Long before Radio was invented, boats could communicate by displaying flags.
Some flags stand for letters or numbers. Others represent words. Still others are repeat flags. Repeat flags are a way of indicating that a letter is repeated without having to stock many copies of the flag.
Most people have seen divers flags. These indicate when a diver is underwater and warns boats to stay away. Other flags might indicate quarantine or warn of other dangers.
Flags are often used in combination with others and this provides an extensive vocabulary. Ships carry a manual that help remind the seamen of the proper use of signaling flags.
Most flags have several meanings depending on circumstances and what other flags are displayed with it. Besides being a letter of the alphabet, a flag can communicate a message, such as a red and white signal flag means H, but also "I have a pilot on board".
Boat racers are familiar with various combinations of flags indicating starts, delays or shortened courses.
Most boat clubs will have their own flag or burgee.
When a boat is dressed up for a special occasion, it will sometimes display signal flags.The Canadian Navy has a Manual of Ceremony that gives the order of ceremonial flag displays.

The Signal flags have a international meaning but some countries have added additional messages to the flags. The UK, Canada and likely most other countries that drink, have an unofficial Gin Pennant. When raised this is an invitation to officers for a celebration.
Signal Flags
Character | Telephony |
Phonetic Pronunciation |
Meanings |
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A -Alfa | AL-FAH | "I have a diver down; keep well clear at slow speed" The ALFA flag is a navigational signal intended to protect the vessel from collision. With three numerals, azimuth or bearing. |
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B -Bravo | BRAH-VOH | "I am taking in, or discharging, or carrying dangerous goods." (Originally used by the Royal Navy specifically for military explosives.) |
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C -Charlie | CHAR-LEE | "Affirmative" With three numerals, course in degrees magnetic. |
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D -Delta | DELL-TAH | "Keep clear of me; I am maneuvering with difficulty" With two, four, or six numerals, date. |
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E -Echo | ECK-OH | "I am altering my course to starboard" Crew at meals |
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F -Foxtrot | FOKS-TROT | "I am disabled; communicate with me" (When flown from an aircraft carrier; Warning; flight operations underway. |
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G -Golf | GOLF | "I require a pilot" When made by fishing vessels operating in proximity of the fishing grounds it means: "I am hauling nets." With four or five numerals, longitude. (The last two numerals denote minutes and the rest degrees.) |
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H -Hotel | HOH-TEL | "I have a pilot on board" |
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I -India | IN-DEE-AH | "I am altering my course to port" |
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J -Juliet | JEW-LEE-ETT | "I am on fire and have dangerous cargo on board: keep well clear of me" or: I am leaking dangerous cargo |
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K -Kilo | KEY-LOH | "I wish to communicate with you." With one numeral, "I wish to communicate with you by..."; 1) Morse signalling by hand-flags or arms; 2) Loud hailer (megaphone); 3) Morse signalling lamp; 4) Sound signals. |
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L -Lima | LEE-MAH | In harbour: "The ship is quarantined." At sea: "You should stop your vessel instantly." With four numerals, latitude. (The first two denote degrees and the rest minutes.) |
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M -Mike | MIKE | "My vessel is stopped and making no way through the water." |
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N -November | NO-VEM-BER | Negative N and C together is used as a distress signal, (no and yes) |
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O -Oscar | OS-CAH | "Man overboard." (often attached to the man overboard pole on boats). With a sinister hoist, the semaphore flag. |
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P -Papa | PAH-PAH | The Blue Peter.In harbour: All persons should report on board as the vessel is about to proceed to sea. At sea: It may be used by fishing vessels to mean: "My nets have come fast upon an obstruction." |
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Q -Quebec | KEH-BECK | "My vessel is 'healthy' and I request free pratique." Pratique is the license given to a ship to enter port on assurance from the captain to the authorities, that she is free from contagious disease. The clearance granted is referred to as Free Pratique. |
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R -Romeo | ROW-ME-OH | "The way is off my ship." With one or more numerals, distance (range) in nautical miles. |
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S -Sierra | SEE-AIR-RAH | "I am operating astern propulsion." With one or more numerals, speed in knots. |
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T -Tango | TANG-GO | "Keep clear of me; I am engaged in pair trawling." With four numerals, local time. (The first two denote hours and the rest minutes.) |
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U -Uniform | YOU-NEE-FORM | "You are running into danger." |
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V -Victor | VIK-TAH | "I require assistance." With one or more numerals, speed in kilometres per hour. |
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W -Wiskey | WISS-KEY | "I require medical assistance." |
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X -Xray | ECKS-RAY | "Stop carrying out your intentions and watch for my signals." |
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Y -Yankee | YANG-KEY | "I am dragging my anchor." |
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Z -Zulu | ZOO-LOO | "I require a tug." When made by fishing vessels operating in close proximity on the fishing grounds it means: "I am shooting nets." With one or more numerals, time (UTC). (The first two denote hours and the rest minutes.) |
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1 -One | WUN | No International meaning Navy Numeral 1 |
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2 -Two | TOO | No International meaning Navy Numeral 2 |
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3 -Three | TREE | No International meaning Navy Numeral 3 |
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4 -Four | FOW-ER | No International meaning Navy Numeral 4 |
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5 -Five | FIFE | No International meaning Navy Numeral 5 |
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6 -Six | SIX | No International meaning Navy Numeral 6 |
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7 -Seven | SEV-EN | No International meaning Navy Numeral 7 |
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8 -Eight | AIT | No International meaning Navy Numeral 8 |
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9 -Nine | NIN-ER | No International meaning Navy Numeral 9 |
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0 -Zero | ZEE-RO | No International meaning Navy Numeral 0 |
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1 -One | WUN | Numeral one (International) These is the numerals used by merchantmen Pennant one (Navy) |
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2 -Two | TOO | Numeral two (International) Pennant two (Navy) |
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3 -Three | TREE | Numeral three (International) Pennant three (Navy) |
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4 -Four | FOW-ER | Numeral four (International) Pennant four (Navy) |
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5 -Five | FIFE | Numeral five (International) Pennant five (Navy) |
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6 -Six | SIX | Numeral six (International) Pennant six (Navy) |
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7 -Seven | SEV-EN | Numeral seven (International) Pennant seven (Navy) |
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8 -Eight | AIT | Numeral eight (International) Pennant eight (Navy) |
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9 -Nine | NIN-ER | Numeral nine (International) Pennant nine (Navy) |
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0 -Zero | ZEE-RO | Numeral zero (International) Pennant zero (Navy) |
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First Substitute | Substitutes (or more accurately repeats) the first flag in the row of flags. This is a way of adding more of the same letters without having many sets of flags. Like the blank tile in Scrabble. Also absence of flag officer. General Recall in a sailing regatta |
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Second substitute | Substitutes for the second flag in the hoist. In other words when the second substitute flag appears, it represents the second letter in the row of flags. | |
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Third substitute | Substitutes for the third flag in the hoist. It represents a repeat of the third letter in the row. | |
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Fourth Substitute | Adds another copy of the fourth flag in the hoist. | |
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Code Answer | Message is understood. Also, numeric decimal point. (International) Flag that follows is from the International Code of Signals. (US Navy) |
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Small Craft Warning | Small craft warning: Sustained wind speeds in the range of 20 to 33 knots inclusive (Atmospheric Environment Service, Environment Canada) This is in the combined ranges of forces 6 and 7 on the Beaufort scale. | |
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Gale warning | Approximately 34 to 47 knots | |
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Storm Warning | Between 48 knots and 63 knots. | |
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Hurricane Warning | Sustained winds of 64 knots, or higher is expected. | |
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Diving Flag | Alpha flag is the International flag for diving. | Used to show that there is a diver below. The red and white divers flag is mainly used in North America and other countries (Italy) while internationally the A flag is more common. The red and white flag often is used as a shop sign to indicate where diving goods and services are offered. Although widely recognized the red and white flag is not a legal requirement although it is permitted. The A flag is a legal requirement. The Alfa flag is primarily intended to protect ships from collision, the diver-down flag is primarily intended to protect divers. |
I try to be accurate and check my information, but mistakes happen.
email me if you find mistakes, I'll fix them and we'll all benefit: Christine
Signal Flags
Very good article on flag communication With Canadian Emphasis but lots of international flag use information.Signaling at sea Good article on Flag Signaling with US Navy emphasis.
Boat navigation and piloting:
Beach Signal Flags used in New Zealand
Surf Shop in Australia sells surfing flags
UK Maritime signal flags article with a couple of Interactive applications.
Hampshire Flag Company UK shop sells maritime flags and more
Japanese Navy Signal Flags Great PDF article by David Dickson in Dreadnought project.org
Article in French on Signal Flags Wikipedia
Radio Phonetic Alphabet
Good Wikipedia Article on various versions and history of the phonetic alphabet.Nautical terms referring to boat hulls
Radar and Radar Reflectors
Small Print
This information is for general knowledge. I make mistakes. Use your head and do your research.