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IALA buoyage: read the marks

The IALA system is how the sea is signposted. Below are the six families of marks, laid out the way they work on the water. Click any mark to see it up close, with its light and a full description.

First: Region A or Region B?

The colours of lateral marks depend on where in the world you are. It is the only difference between the regions: the other five families are the same everywhere.

Region A

Europe, Africa, Australia, New Zealand, the Gulf and most of Asia.

Red to port, green to starboard, entering from seaward.

Region B

The Americas, Japan, Korea, the Philippines.

The other way round: red to starboard, green to port. Hence „red right returning”.

Lateral marks

They mark the sides of the channel. Entering from seaward, you leave the port-hand mark to port and the starboard-hand mark to starboard.

port hand
starboard hand

Where the channel divides

A modified lateral mark with one horizontal band in the other colour. It points to the preferred channel, and its Fl(2+1) light separates it from an ordinary lateral mark.

preferred channel to starboard
preferred channel to starboard
preferred channel to port
preferred channel to port

They say on which side the safe water lies: north, east, south or west of the mark. Laid out here like the compass.

Northpass on its north side
Westpass on its west side
the dangeryou pass it on the safe side
Eastpass on its east side
Southpass on its south side

The danger sits in the middle, and the cardinal marks around it tell you which side to pass. A north mark means safe water lies to its north, so you pass it on the north side. East on the east side, and the same for south and west.

The other marks

Common to both regions. Each has a look and a light you cannot confuse with anything else.

Light characteristicsFl, Q, VQ, LFl, Iso, Oc and the 3/6/9 clock of the cardinal marks. IALA marks quizRecognise the mark by day and by its light. Free, no sign-up.

Facts (colours, shapes, topmarks, light rhythms) follow the IALA Maritime Buoyage System (MBS ed. 2.0). The drawings are our own vectors. The rhythm and colour in the drawings are illustrative: always check the real characteristics of a buoy on the chart and in the list of lights.