When you move a vessel in or out of a harbor, the red and green buoys are some of the most important markers you will see. They show you the safe sides of a channel and help you avoid shallow water, rocks, and other hazards. If you misread them, you may face grounding, collision, or traffic confusion. This guide explains what these colors really mean and how to use them during daily operations.
Why These Buoys Matter
Red and green buoys guide all types of vessels—small boats, cargo ships, and offshore support vessels. Crew need them for safe navigation, shipowners rely on them to avoid accidents and insurance issues, and terminal operators depend on correct buoy positions to manage ports smoothly.
Understanding the Basic System
Most countries follow the IALA (International Association of Marine Aids to Navigation and Lighthouse Authorities) buoyage system. There are two regions:
- Region A: Europe, Africa, Asia, Australia
- Region B: North & South America, Japan, Korea, the Philippines
Both regions use red and green buoys, but the side on which they appear changes. These buoys belong to the lateral mark system, meaning they mark the two sides of a navigational channel.
What Red and Green Buoys Mean
Region B (Most common rule for the Americas)
A simple phrase: “Red on the right when returning.”
- Returning from the sea toward the harbor: Keep red buoys on your right (starboard).
- Green buoys stay on your left (port).
Region A
The opposite rule applies.
- Entering a harbor: Keep green buoys on your right and red buoys on your left.
Shapes and Numbers
- Red buoys usually have even numbers.
- Green buoys usually have odd numbers.
- Shapes may include:
- Can shape: typically on the port side
- Cone shape: typically on the starboard side
Lights
At night, buoys show a light with the same color as the buoy. The flash pattern helps you confirm which buoy you are seeing, especially in busy or low-visibility areas.
How to Use These Buoys When Navigating
When entering a harbor
- Know whether your region is IALA A or B.
- Keep the correct buoy color on the proper side.
- Slow down and scan your radar/AIS when sight is unclear.
- Maintain communication with port control when traffic is heavy.
When leaving a harbor
The rules reverse, because you are heading “outbound.”
- In Region B, green will be on your right heading out.
- In Region A, red will be on your right going out.
Best Practices for Terminal/Port Operators
- Make sure buoy colors stay bright and visible.
- Test lights and replace weak or dead bulbs quickly.
- Check anchor points and positions, especially after storms.
- Report any drifted or damaged buoy to the local authority.
Common Mistakes to Avoid
- Mixing up regions. Always confirm your region before entering a new port.
- Ignoring buoy drift. A buoy that moved even a few meters can lead to grounding in shallow harbors.
- Assuming red and green are the only markers. Remember: yellow, black, and other special marks also guide you around hazards.
- Not checking the latest notices. Always check the latest “Notice to Mariners” before sailing.
Final Thoughts
Red and green buoys are simple to read once you understand your region and the basic rules. They help you stay in the safe channel and keep traffic running smoothly. Whether you’re steering a tug, managing a berth, or owning a vessel, correct buoy recognition protects people, ships, and port assets.
FAQ
1. How do I know if I’m in Region A or Region B?
Check your local chart. It always states the IALA region. You can also ask port control.
2. What if the buoy color looks faded or wrong?
Use the light color and number as confirmation. If it still looks wrong, report it to the port authority.
3. What should I do if a buoy drifts?
Do not rely on its position. Report it immediately. Wait for a correction or updated navigation notice.
4. Do small boats follow the same rules?
Yes. All vessels in the channel—large or small—use the same buoyage rules.
5. Can red and green buoys mark hazards?
No. They mark channel sides. Hazards are usually marked by other buoy types like isolated danger marks or special marks.