At first glance, one might assume that maritime buoyage speaks a universal language. Yet, two distinct systems are in use globally. Why this peculiarity? Let’s explore the history behind Regions A and B and see how they continue to guide mariners safely today.
Much like road signs guide drivers on land, maritime buoyage systems mark navigational routes and signal hazards to ensure safe passage at sea. Aids to navigation — whether deployed offshore or on land — help mariners find their bearings, especially when approaching harbours, rivers, or estuaries.
Unlike road signage, which is largely standardized worldwide, maritime marking historically reflected a wide range of local traditions, leading to a lack of consistency across regions.
Until 1976, more than thirty different buoyage systems were in use worldwide, many with contradictory rules. This lack of standardization complicated international navigation and posed safety risks for seafarers crossing different maritime zones.
To address this complex issue, it was agreed to establish two global systems:
These were later integrated under a unified framework known as “The IALA Maritime Buoyage System”, as per the standards of the International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA).
Historically, Europe, Africa, Asia, and Oceania placed red buoys to port when entering a harbour. Conversely, in North and South America, Japan, and the Philippines, red buoys were positioned to starboard. Enforcing a single global standard would have disrupted long-standing practices and potentially confused mariners.
The chosen solution was therefore pragmatic: maintain two systems, each assigned to specific geographic zones:
While the basic principle remains consistent — red and green indicate the sides of a navigable channel — the interpretation differs depending on the system:
- Red = Port side when entering harbour
- Green = Starboard side
- Red = Starboard side when entering harbour
- Green = Port side
Mnemonic tip for Region B: “Red Right Returning” — keep red to your right when entering the port.
Today, approximately 80% of the world uses System A, while 20% follows System B. Though this may seem counterintuitive, navigational safety remains uncompromised because:
In essence, this duality respects maritime heritage while maintaining high safety standards.
The idea of adopting a single global buoyage system is still periodically raised in international forums. However, as long as historical practices remain deeply rooted and safety is not compromised, the coexistence of both systems is likely to continue.
At GISMAN, we partner with maritime authorities and port operators across the globe to deliver reliable, sustainable, and IALA-compliant buoyage solutions.
Because beyond regional systems, one mission unites us all: Ensuring the safety of mariners and protecting the marine environment — everywhere in the world.
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