IALA Maritime Buoyage System

The IALA Maritime Buoyage System harmonized the world’s conflicting buoyage conventions into a single framework with two complementary regions. Region A places red lateral marks to port and green to starboard when entering from seaward; Region B reverses the colours, red to starboard. Both regions share identical cardinal marks (referenced to north, east, south, west), isolated-danger marks, safe-water marks, and special marks, so only the lateral-mark colour scheme differs. The split is the historic compromise that ended decades of incompatible national systems.