The first time I brought my own boat into a French harbour, I nearly put a red can to the wrong side. I had spent a decade sailing the east coast of the United States, where the rule drummed into me was "red, right, returning". In France that mnemonic will run you onto the rocks. France uses IALA Region A, and the colours are the other way round from what an American or a Canadian carries in muscle memory.
If you cruise in from the UK, the Netherlands, Germany or Scandinavia, you already use Region A at home, so the colours will feel familiar. But the way France lays out approaches, the density of cardinal marks off the Brittany coast, and the conventional direction of buoyage still catch people out. Worth getting straight before you make your first landfall.
The two systems, and which one you are in
The International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA) split the world into two buoyage regions back in 1980. Region B covers North and South America, Japan, South Korea and the Philippines. Region A covers everywhere else: all of Europe, Africa, most of Asia, Australia and India. France sits squarely in Region A.
The single difference that matters most is lateral mark colour:
In Region A, port-hand marks are red and starboard-hand marks are green.
In Region B, it is reversed: port-hand marks are green, starboard-hand marks are red.
So the American "red, right, returning" is a Region B rule. In France, returning from seaward, you keep red to port and green to starboard. If you have only ever sailed the US east coast, retrain your eyes before you arrive. I taped a hand-written note to my chart table for the first week: RED TO PORT INBOUND. It looked silly and it worked.
Lateral marks: shape, colour, topmark, light
When you approach a French port or a buoyed channel from seaward, here is what you read.
Port-hand mark: red, can-shaped (a flat-topped cylinder), with a red can topmark if fitted. The light, if lit, is red, and it can flash in any rhythm.
Starboard-hand mark: green, conical (pointed top, sometimes called a nun in North America), with a green cone topmark pointing up. The light is green.
Keep red cans to your left and green cones to your right as you head in from the open sea, and you are in the channel. The shapes are your backup when light or distance washes out the colour: a flat-topped can is always port, a pointed cone is always starboard, no matter how faded the paint.
The direction of buoyage is the part people miss
Colour only tells you which side once you know which way is "in". IALA defines a conventional direction of buoyage: generally from seaward towards a harbour, river or estuary, or in the absence of that, clockwise around a landmass. French charts mark this direction with a small magenta arrow.
This matters enormously along a coast like Brittany, where you are not always heading into a port. Coast-parallel, the convention in the Channel and along the Atlantic seaboard runs broadly from the southwest to the northeast (the flood-tide direction). Get the convention wrong and you read every lateral mark backwards. When in doubt, check the magenta arrow on the chart, and if a passage feels confusing, slow down and confirm before committing. Knowing how tides set in these waters helps; if you are new to big tidal ranges, our piece on brittany tides for mediterranean sailors explains why the current here is a force in its own right.
Cardinal marks: the Brittany speciality
Nowhere in my European sailing have I seen as many cardinal marks as around the rocks of north and south Brittany. Cardinal marks tell you where the safe water lies relative to the danger, using the four compass quadrants.
A north cardinal: black above yellow, two cone topmarks both pointing up. Pass to the north of it.
A south cardinal: yellow above black, two cones both pointing down. Pass to the south.
An east cardinal: black with a single broad yellow band, cones pointing away from each other (base to base). Pass to the east.
A west cardinal: yellow with a single black band, cones pointing towards each other (point to point, like a wineglass or a W for west). Pass to the west.
The topmark trick that saved me more than once: the cones point towards the black band. North has black on top, so cones point up. South has black at the bottom, so cones point down. The lights are white and quick or very quick flashing, and the number of flashes follows a clock face: east is three, south is six (plus a long flash), west is nine. North is continuous quick or very quick flashing with no breaks. If you plan to thread the inshore passages off the chenal du four and raz de sein, you will be reading cardinals constantly, so drill them before you go.
Leading lines and the marks that point you in
French port approaches lean heavily on transits, called alignements on the chart, two marks that you line up one behind the other to hold a safe track in. They are everywhere in Brittany and along the Atlantic coast, often painted as bold geometric shapes on the shore or as lit towers for night use. When the two marks are vertically in line, you are on the leading line; when the front one drifts left, you steer left to bring it back, and the same to the right. It is a deceptively powerful tool through a narrow rock-bound channel, and far more precise than chasing buoys one at a time. Many of the trickier French entrances are designed to be taken on a transit rather than by eye, so check the chart for one before you commit to an unfamiliar approach.
Sector lights do a similar job at night. A single light shows white in the safe sector and red or green in the danger sectors either side, so a glance at the colour tells you whether you are on track. Drift out of the white and into the red, you have strayed to one side; into the green, the other. Learning to read these from the chart's light characteristics before you arrive saves a great deal of squinting in the dark.
Other marks you will meet
Isolated danger mark: black with one or more broad red horizontal bands, two black spheres as a topmark. It sits on top of a danger with navigable water all around. White light, two flashes in a group.
Safe water mark: red and white vertical stripes, a single red sphere topmark. Found at the seaward end of a channel or mid-channel. Often where you pick up the buoyed approach to a port.
Special marks: yellow, yellow X topmark, yellow light. These mark things like spoil grounds, cables, aquaculture and racing buoys. They carry no navigational "side" meaning, so do not treat a yellow buoy as a channel edge.
Emergency wreck marking buoy: blue and yellow vertical stripes, a yellow cross topmark, alternating blue and yellow light. IALA introduced this after the loss of the Tricolor in the Dover Strait in 2002, and it goes up quickly over a fresh wreck before the chart catches up. Treat it as a hard avoid.
Three habits that keep visitors safe
Match what you see to the chart, not to the system you grew up with. A current, corrected chart is not optional in French waters; it is a legal requirement and a sanity check. If you are buying or refitting a boat to bring over, our notes on buying a used sailboat hull inspection cover the survey side, but the chart plotter and paper charts deserve the same scrutiny.
Read shape and topmark when the light fails you. At dusk, against a low sun, or in the haze that hangs over the Atlantic coast, colour is the first thing to go. A can is a can and a cone is a cone.
Confirm the direction of buoyage before you trust a lateral mark. The magenta arrow is the whole game. I have watched experienced skippers, fresh off a long passage and tired, follow green-to-port out of habit and end up confused in a narrowing channel. One glance at the arrow settles it.
France is a wonderful place to learn this system in earnest, because it throws everything at you within a single day's sail: dense lateral channels into the marinas, a forest of cardinals around the offshore rocks, and the occasional wreck buoy where the seabed has shifted. Get the colours and the direction fixed in your head before you arrive, and the rest is just careful reading. The boat does not care which country you learned to sail in. It only cares that you keep the red to the correct side.
