Comparisons
IALA Region A and Region B — what A vs B actually changes
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.
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 — side-by-side
| Aspect | Region A | Region B |
|---|---|---|
| Port-hand lateral mark | RED can / cylinder | GREEN can / cylinder |
| Starboard-hand lateral mark | GREEN cone | RED cone |
| Memory aid (returning from sea) | Red to port when returning in the conventional direction | Red to starboard when returning in the conventional direction |
| Preferred-channel mark (port preferred) | Green with one broad red band; green cone, point up | Red with one broad green band; red cone, point up |
| Cardinal marks N · E · S · W | Identical | Identical |
| Isolated danger mark | Identical — black with red bands, two black spheres | Identical |
| Safe water mark | Identical — red/white vertical stripes | Identical |
| Special marks | Identical — yellow with yellow X topmark | Identical |
| Emergency wreck marking buoy | Identical — blue/yellow vertical stripes | Identical |
| Countries (examples) | UK · Spain · France · Italy · Greece · Croatia · Germany · India · Australia · South Africa | USA · Canada · Mexico · Brazil · Japan · South Korea · Philippines |
Countries by IALA region
| Country or area | IALA region | Lateral marks |
|---|---|---|
| Europe, including Greenland and the Faroe Islands | Region A | Port-hand RED, starboard-hand GREEN |
| Africa | Region A | Port-hand RED, starboard-hand GREEN |
| Mainland China, India and most of Asia | Region A | Port-hand RED, starboard-hand GREEN |
| Australia and New Zealand | Region A | Port-hand RED, starboard-hand GREEN |
| North, Central and South America and the Caribbean, excluding Greenland | Region B | Port-hand GREEN, starboard-hand RED |
| Japan, South Korea, Taiwan and the Philippines | Region B | Port-hand GREEN, starboard-hand RED |
| Guam | Region A | Port-hand RED, starboard-hand GREEN |
| North Korea and unassigned islands on this teaching map | Check local charts | Do not infer a region from political sovereignty or a nearby country |
Which region am I in?
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.
- 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.
- Study overview. Greenland and Guam use Region A. Grey areas are left unclassified; check local charts for island and territorial exceptions.
- North Korea is left unclassified because the IALA and NGA references disagree. Pacific islands without verified assignments are also grey.
Keep going
Frequently asked questions
Is the United States in IALA Region A or Region B?
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 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.
Does Europe use Region A or Region B?
A: Europe, Africa, most of Asia, Australia and New Zealand.
What is a preferred-channel mark?
At a channel division, a modified lateral mark identifies the preferred channel: it retains the lateral main colour and topmark, with one broad horizontal band of the opposite colour. Its light is composite group flashing Fl(2+1), in the main colour. In the conventional direction, keep the can-shaped mark to port for a preferred channel to starboard; the arrangement reverses for a preferred channel to port.
Do cardinal marks differ between 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 countries are in 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 the IALA system the same in both regions apart from lateral marks?
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.
Last reviewed: