Interactive trainer
The same harbour entrance, both regions. Toggle between them or put them side by side and see exactly what changes in the IALA system: lateral colours reverse; the distinctive shapes and other mark types retain their meanings.
Follow the charted direction of buoyage. The diagrams show can/cone examples; pillars and spars are also used. Lights and topmarks may not be fitted. Local systems, including U.S. Western Rivers and ICW markings, need their own guidance.
IALA Region A
Europe, Africa, Australia, New Zealand, most of Asia and the Gulf
Entering from seaward in the direction of buoyage. Shapes and topmarks are the same in both regions — cans to port, cones to starboard — only the colours swap. Cardinal, isolated danger, safe water and special marks share their IALA meanings in both regions. Check local chart conventions and variations.
| Mark | Region A | Region B |
|---|---|---|
| Port-hand lateral mark | Red can; red light | Green can; green light |
| Starboard-hand lateral mark | Green cone; green light | Red cone (nun); red light |
| Preferred channel to starboard | Red can with a green band; red light Fl(2+1) | Green can with a red band; green light Fl(2+1) |
| Preferred channel to port | Green cone with a red band; green light Fl(2+1) | Red cone with a green band; red light Fl(2+1) |
| Lateral shapes and topmarks | Can to port, cone to starboard | Can to port, cone to starboard (same) |
| Cardinal marks | Yellow and black, two cones, white light | Identical |
| Isolated danger mark | Black with red band(s), two black spheres, white Fl(2) | Identical |
| Safe water mark | Red and white vertical stripes, red sphere, white light | Identical |
| Special mark | Yellow, yellow X topmark, yellow light | Identical |
| Where it applies | Europe, Africa, Australia, New Zealand, most of Asia | The Americas, Japan, Korea, the Philippines |
Direction of buoyage: entering from seaward, or as shown on the chart by the buoyage arrow. Source: IALA R1001, Edition 2.0.
Where a channel divides, a modified lateral mark shows which branch is preferred. The base colour is the region's lateral colour for the side you keep it on; the band is the other colour. The Fl(2+1) rhythm is reserved for these marks in both regions.
4 quick questions. Pick an answer, check it, and read why.
Check yourself
Question 1 of 4
Navigation
Red to port or red right returning? How the two IALA buoyage regions differ, what “direction of buoyage” really means, preferred-channel marks, and the marks that are identical everywhere — with a side-by-side diagram.
9 min read
Navigation
North, east, south, west cardinal buoys explained — what the two cones mean, why the black bands follow the cones, the clock-face trick for the light rhythms, and how to use them without shaving the danger.
6 min read
Navigation
The difference between navigation and pilotage, what goes into a pilotage plan — marks, transits, clearing bearings, depths, tides and the point of no return — and how to run the plan from the cockpit without a chart table.
8 min read
Editorial check: . Source: IALA R1001 ↗
Region A buoyage is drilled in the Day Skipper Theory course (49 questions on buoyage and marks); Region B in Basic Keelboat Theory (48 questions on basic navigation and buoyage). Illustrated, explained, offline.
SailQuiz is an independent study aid. It is not affiliated with, endorsed by, accredited by, or otherwise connected to the ASA, US Sailing, the RYA, the USCG, or any other certifying body, and it is not a substitute for their official training or examinations.
