A Beginner’s Guide to Nautical Flags & Their Meanings

As a boater, it's important to understand nautical flags and their meaning. Some flags may alert you to a weather warning, while others may help you communicate with other ships on the water.

Nautical flags are made with a sequence of 26 square flags. Each flag represents a letter of the alphabet. There are also ten numbered flags, one answering pendant, and three substitutes or repeaters.

Nautical Flags

You will only find nautical flags in a few specific colors because they are easily recognizable. These colors are:

  • Blue

  • Yellow

  • White

  • Black

  • Red

There are different signals and messages specific flags or combinations of nautical flags communicate. Let's look at a few of the different types of flag signals and what they mean.

Weather Warning Signals

Four signals are created from nautical flags to signal different weather warnings. All-weather warning signals are communicated with red and/or black flags.

A small craft warning is simply a single red pendant flag, while a small craft advisory (gale warning) is two red pendant flags.

A storm warning is signaled by a single square red flag with a second black square in the center. If two square red flags with black squares are present, it's meant to communicate a hurricane warning.

Signals Broken Down By Number Of Flags

The number of flags present has a meaning. Here's the breakdown

  • One-Flag Signals - Urgent or Common

  • Two-flag Signals - Distress or Maneuvering

  • Three-Flag Signals - Points of the Compass, Standard-Times, Verbs, Punctuation, Code and Decode Signals

  • Four-Flag Signals - Geographic, Names of Ships, and Bearings

  • Five-Flag Signals - To Relate Position and Time

  • Six-Flag Signals - Indicate West, East, South, or North in Longitude or Latitude Signals

  • Seven-Flag Signals - Longitude with more than one-hundred degrees

Nautical flags are also used in racing to communicate messages to competitors.

International Nautical Flag Meanings

Each flag representing a letter of the alphabet has a meaning. The meanings are as follows:

  • A or Alpha - keep clear, diver down

  • B or Bravo - carrying dangerous cargo

  • C or Charlie - yes

  • D or Delta - keep clear

  • E or Echo - altering course to starboard

  • F or Foxtrot - I am disabled

  • G or Golf - I want a pilot

  • H or Hotel - a pilot on board

  • I or India - altering course to port

  • J or Juliet - vessel on fire, keep clear

  • K or Kilo - I want to communicate with you

  • L or Lima - stop your vessel instantly

  • M or Mike - my vessel is stopped

  • N or November - no

  • O or Oscar - man overboard

  • P or Papa - vessel is about to sail

  • Q or Quebec - I request free pratique

  • R or Romeo - reverse course

  • S or Sierra - engines are going astern

  • T or Tango - keep clear

  • U or Uniform - you are heading into danger

  • V or Victor - require assistance

  • W or Whiskey - require medical assistance

  • X or X-ray - stop your intention

  • Y or Yankee - I am dragging anchor

  • Z or Zulu - I require a tug

Understanding the meaning of nautical flags can help you communicate and receive messages on the water.