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IALA Maritime Buoyage System

IALA Buoyage System

The IALA Maritime Buoyage System sets out the marks you'll meet at sea: lateral, cardinal, isolated danger, safe water and special marks. Only the lateral marks change between the two regions: in Region A red marks are left to port when entering harbour, in Region B they are left to starboard. Region B covers most of the Americas plus Japan, South Korea, Taiwan and the Philippines; most other waters use Region A.

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Decide

One mark from each family. Can you name them before you read on?

Question 1/6

You are returning from seaward in Region A. Which mark do you leave to port?

What IALA stands for — and what the buoyage system is

IALA is the International Organization for Marine Aids to Navigation, an intergovernmental organisation since 22 August 2024. Its abbreviation comes from its former name, the International Association of Marine Aids to Navigation and Lighthouse Authorities. IALA publishes standards and recommendations that help maritime authorities harmonise buoys, beacons, lights and other aids to navigation.

The IALA Maritime Buoyage System defines marks by their colour, shape, topmark and light rhythm. This site covers six buoyage families: lateral, cardinal, isolated danger, safe water, special and emergency wreck marks; the system also covers other aids, including lighthouses. The combined system was agreed in 1980 and its implementation agreement was signed on 15 April 1982. Regions A and B differ in the colours of lateral marks, including preferred-channel marks.

IALA buoysThe six families of marks: buoys, beacons and their lights

Every family is recognised by its colour, its shape, its topmark and its light rhythm. Open one to study it in depth.

IALA Region A and BWhich countries are Region A and which are Region B?

IALA regions around the world

Region ARegion B
IALA regions around the worldRegion A: Europe, Africa, most of Asia, Australia and New Zealand. Region B: The Americas, Japan, South Korea, Taiwan and the Philippines. Study overview. Greenland and Guam use Region A. Grey areas are left unclassified; check local charts for island and territorial exceptions.

Region A

Europe, Africa, most of Asia, Australia and New Zealand

Region B

The Americas, Japan, South Korea, Taiwan and the Philippines

Check local charts

Study overview. Greenland and Guam use Region A. Grey areas are left unclassified; check local charts for island and territorial exceptions.

East Asia and the western Pacific

East Asia and the western PacificJapan: Region B. South Korea: Region B. Taiwan: Region B. Philippines: Region B. Guam: Region A. North Korea is left unclassified because the IALA and NGA references disagree. Pacific islands without verified assignments are also grey.
  1. Japan (B)
  2. South Korea (B)
  3. Taiwan (B)
  4. Philippines (B)
  5. Guam (A)
Sources

North Korea is left unclassified because the IALA and NGA references disagree. Pacific islands without verified assignments are also grey.

Region A

Region A

  • Europe — every Atlantic, Mediterranean, Baltic and Black Sea coast
  • Africa — the whole continent, Atlantic, Mediterranean and Indian Ocean coasts alike
  • The Middle East and the Gulf
  • India, and the rest of South Asia
  • Most of East and South-East Asia
  • Australia and New Zealand
Region B

Region B

  • The United States and Canada
  • Mexico, Central America and the Caribbean
  • South America — the whole continent
  • Japan
  • South Korea
  • Taiwan
  • The Philippines
IALA Region A and Region B — what A vs B actually changesRegion A vs Region B — side-by-side

The IALA Maritime Buoyage System, in plain English

The IALA Maritime Buoyage System harmonises fixed and floating aids to navigation. The current R1001 recommendation is edition 2.0, June 2023. IALA became an intergovernmental organisation on 22 August 2024.

This site covers lateral, cardinal, isolated danger, safe water, special and emergency wreck marks. R1001 also covers other aids, including lighthouses. Special marks can include mobile aids marking dangerous floating objects; emergency wreck buoys can mark new dangers beyond wrecks.

The lateral colours change: in Region A, port-hand marks are red and starboard-hand marks green; in Region B, port is green and starboard red, following the conventional direction of buoyage. The other mark families use the same system in both regions.

Region A vs Region B — what actually changes

AspectRegion ARegion B
Port-hand mark colourRed (can shape)Green (can shape)
Starboard-hand mark colourGreen (cone shape)Red (cone shape)
Memory aid"Red right going TO sea""Red right returning from sea"
Cardinal marksIdentical — same colours, same topmarks, same lightsIdentical — same colours, same topmarks, same lights
Isolated danger / safe water / special / wreck marksIdentical worldwideIdentical worldwide
Countries (examples)UK, Spain, France, Italy, Greece, India, Australia, South AfricaUSA, Canada, Mexico, Brazil, Japan, South Korea, Philippines

Practise IALA buoyage

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Frequently asked questions

What is the difference between IALA Region A and Region B?

The lateral colours change: in Region A, port-hand marks are red and starboard-hand marks green; in Region B, port is green and starboard red, following the conventional direction of buoyage. The other mark families use the same system in both regions.

Which IALA region covers the United States?

The US mainland, Alaska and Hawaii use Region B. Some US territories use Region A, including Guam; check local charts when sailing in island territories.

What does "red right returning" mean?

The lateral colours change: in Region A, port-hand marks are red and starboard-hand marks green; in Region B, port is green and starboard red, following the conventional direction of buoyage. The other mark families use the same system in both regions.

What do the two black spheres on a buoy mean?

Isolated danger marks have two black spheres (balls) as topmark. An isolated danger mark is on or near a danger with navigable water around it. Consult charts and nautical publications for the extent of the danger and safe passing distance.

What is an emergency wreck marking buoy?

The emergency wreck marking buoy marks new dangers, including newly discovered wrecks. The competent authority determines further marking once the danger is removed or its information has been sufficiently promulgated. 1 s blue + 0.5 s darkness + 1 s yellow + 0.5 s darkness; period 3 s.

What does IALA stand for?

IALA is the International Organization for Marine Aids to Navigation. It became an intergovernmental organisation on 22 August 2024, retaining the abbreviation of its former name, the International Association of Marine Aids to Navigation and Lighthouse Authorities. It publishes the Maritime Buoyage System.

What is the IALA buoyage system?

The IALA Maritime Buoyage System harmonises the meaning of navigation marks through their colour, shape, topmark and light rhythm. Its buoyage families include lateral, cardinal, isolated danger, safe water, special and emergency wreck marks. It also covers other aids such as lighthouses. Regions A and B differ in the colours of lateral marks, including preferred-channel marks.

Which countries use IALA Region B?

Region B includes the Americas apart from Greenland, plus Japan, South Korea, Taiwan and the Philippines. Greenland and Guam use Region A. Check local charts for island and territorial exceptions.

Is there a PDF of the IALA buoyage system Region A and B?

There is no file to download here. The Region A vs Region B comparison page carries the whole A/B difference as one table plus a country-by-region table, and your browser can print it or save it as a PDF from its own print dialog.