Driving down the road, we’ve all seen the various signs that help direct traffic. But how do you know where to go when you’re in a boat? Boat buoys and markers, that’s how. Boating buoys can be confusing, though. There are many different types and meanings, including telling boaters where the rocks are so they can be avoided, for example. You can see that the importance of knowing your boating buoys is not only vital for safe boating but could save you from being involved in a shipwreck.
We will review the international buoy and marker system here. This easy-to-follow guide will explain all the different buoys and markers and their meanings. Feel free to bookmark this page so you can easily reference it from the helm of your boat.
Applicable Definitions Relating To Buoys And Markers
- Bifurcation – A division of something into two or more branches
- Buoy – An anchored float serving as a navigational mark, to show hazards, or for mooring.
- Fairway – A channel that may be traveled or navigated by a ship or vessel. The channel can be thought of as a ‘highway’ in the water. It is often in the center of a body of water, typically bays, rivers or harbors. The idea is to control the flow of boat traffic in an area by directing it along a fairway.
- Marker – An object used to indicate a position, place, or route.
- Mooring – A point of anchor for a boat, ship or vessel.
- RACON – A radar transponder (RAdar beaCON) that can be identified and located by its response to a specific radar signal.
A Little Info About Navigation In International Waters
The best defense is a strong offense, in terms of information that is. Arming yourself with knowledge before you decide to take a boat out on the water in another country is always a bright idea. You can land yourself in some pretty hot water by not following the rules, no pun intended.
There may be some variations to the rules you may or may not be accustomed to. For example, when traveling inland on a boat, sounding a horn is a signal of your intent to move your vessel a certain way. When you are out in international waters, sounding your horn is a signal that you are taking action, not just that you intend to do so. Therefore, it’s wise to know what the rules are before you embark on your adventure.
Most countries around the world follow the international system of navigation. This system has rules that boaters must obey, just like obeying the speed limit when driving your car. Not obeying these rules can have some fairly severe penalties, so stay informed and boat safely.
Systems Of Navigation
Here in North America, we abide by the International Association of Marine Aids to Navigation Lighthouse Authorities Maritime Buoyage System. Say that three times fast. For short, it is known as the IALA Maritime Buoyage System, often referred to as simply IALA.
This system is used worldwide. However, there is one huge difference depending on where you happen to be. The IALA system divides the world map into two distinct regions, A and B. North America is in region B.
Here’s this huge difference I’m referring to. In Region B, starboard buoys are red, and port buoys are green. In region A, these colors are reversed. As I mentioned, this is a huge difference and a costly mistake if you are unaware and trying to traverse waters in the region you aren’t accustomed to. See the map below for the two regions.
Fixed Navigational Aids – Markers
Markers are similar to buoys in the sense that they convey a lot of navigational information. However, there is one big difference. Markers are fixed on solid ground. Whereas buoys are basically anchored floats. Markers might be marking where rocks are, anchorage points, and so on. Not to be confused with military marker buoys, which are typically used in warfare. The pyrotechnic flare distinguishes military marker buoys or smokes they use to mark a particular location. Common locational markers do not use any pyrotechnics or smoke-producing effect.
Major Lighted Navigational Aids
These structures are typically equipped with a large emergency light and often also a fog signal or RACON. Each country has its own list of lights, buoys, and fog signals, which is far too many for this article (it would take well over 300 pages for me to list all the world’s MLNAs). So, I’ve included references only from Canada and the United States.
Canada’s List Of Lights, Buoys, and Fog Signals
United States Department of Homeland Security Navigation Center Light List
So, what is a major lighted navigational aid? Commonly, we know the lighthouse as the most famous.
If you are using navigational equipment or maps correctly, then you will see these sorts of markers on your map. They will look something like the one shown in the following example.
As you can see in the above example, the position of the lighthouse is shown in this map. It is marked with a purple pointer and the letters RC and the word Racon, in italics below. There are also some other letters and numbers in black off to one side of the marker location on the map. These letters and numbers are a form of coded information about how the light looks and displays. That way, if you are out on a boat on the water, you can identify the significant lighted marker by the way it looks and then correspond that to the information on your navigation system or map. Here’s how this code works. We’ll use the code from the example above.
FI 6s 21m 17M
Fog Sig (2)60s
The first part of the code, in this case, Fl, describes the light flash type. The following chart lists the different flash types you might encounter when navigating your boat.
| Description | Visual Characteristic | Abbreviation |
| Alternating |  | Alt. R.W.G. |
| Fixed |  | F. |
| Flashing |  | Fl. |
| Group Flashing |  | Gp Fl.(2) |
| Group Occulting |  | Gp Occ(3) |
| Isophase |  | Iso. |
| Morse |  | Mo.(letter) |
| Occulting |  | Occ. |
| Quick Flashing |  | Qk.Fl. |
| Very Quick Flashing |  | V.Qk.Fl. |
The next part of the sequence is the first number set.
FI 6s 21m 17M
Fog Sig (2)60s
In the example, the 6s tells us the length of time for the flashing sequence from beginning to end.
FI 6s 21m 17M
Fog Sig (2)60s
Next, the 21m tells us that the elevation of the light is 21 meters (68.89 ft). The elevation of the light is essential for triangulating distance. And speaking of distance:
FI 6s 21m 17M
Fog Sig (2)60s
The last part of the first line of numbers and letters, in this example, 17M, tells us that the nominal range of the light is 17 nautical miles. That means that past this distance in clear conditions, you won’t be able to see the light. This helps ships identify how far away the hazard is through triangulation calculations.
FI 6s 21m 17M
Fog Sig (2)60s
The final line of our example tells us that there is a fog signal that sounds twice every 60 seconds.
Minor Lighted Navigational Aids
These are basically the same as marker buoys, but they are fixed on solid ground. These aids are often found on either side of narrow channels that may not have room for in-water buoys. They, too, will be marked on a map similar to the example above.
Ranges
A range is made of two or more navigation marks that are set apart and at different heights. Again, these, too, will be marked on a nautical map. Range markers are used by the boat to ensure they are on the recommended path. This is the case if the markers line up to the view from the boat. Notice how they will look from the perspective of a boat, when lined up (picture on right).
Sector Lights And Landfall Aids
Sector lights and secondary landfall aids are, again, fixed beacons that indicate a specific area by the use of multicolored and multi-directional lighting. Take a look at the following graphic. Notice how the light that is visible from the water will change depending on the perspective of the boat. Or, to be clear, the light does not change, but depending on the position of the boat, the boat will see different colored light.
No Anchorage Signs
These are pretty straightforward. You are not allowed to drop anchor in areas designated as no anchor zones. This may be due to a gas or fiber optic line running along the seabed. The zone will be designated on a map using a dotted T line with an anchor in the middle that has an X through it. Also noted via signage on the shore nearby or if out away from shore then a sign on a buoy will likely be in the no anchor zone.
Standard Day Beacons
When I first saw the term day beacon, or day beacon, as some write it, I thought these must only be used during the day. And I was right. Day beacons are basically just signs, typically used in shallow water and relatively inexpensive.
There are four basic day beacons, each with its own meaning. You’ll find them below.
Port Hand Day Beacon
This beacon typically has a green fluorescent or black central square with a white border. The entire thing then has an additional border in green reflective. Sometimes, there is also a number in white in the central square.
This number can be referenced on marine charts when it is displayed on the day beacon.
When you are traveling upstream, you must keep this day beacon on your port side (left).
Port Junction / Bifurcation Day Beacon
The port side junction day beacon, also referred to as the port bifurcation, begins with a green reflective square in the center. Around it is a diamond in white, or rather another white square, but turned 45 degrees to appear oriented like a diamond. This white diamond then has a red border, usually fluorescent.
This day beacon tells us that the channel is split. This division can be taken in either direction. If you want to take the right direction, for example, you would keep this day beacon on your port side (left side).
Starboard Junction / Bifurcation Day Beacon
This day beacon begins with a red reflective triangle in the center. Again, like the port junction day beacon, it then has a white diamond bordered with red.
Like the port junction day beacon, this day beacon tells us 
This day beacon should be kept on your starboard side (right side), when the direction you want is the left one, for example.
Starboard Hand Day Beacon
The last of the four common day beacons is the starboard hand day beacon. This one consists of a central red fluorescent triangle with a white border, which is then bordered by another red fluorescent triangle.
The starboard hand day beacon is to be kept on your starboard or right side when traveling upstream.
Lateral Navigational Buoys
Navigational buoys are buoys that mark out boating lanes and specifically deal with navigating your boat in the appropriate direction and place. Although technically, even a marker is navigational, we think the buoys deserve their own section. What is the difference? Markers are fixed to solid ground. Buoys float out in the water and are anchored in place.
The following are all the common buoys. On each graphic, there are two bars representing the light sequence and color that the buoy provides when equipped with a light.
Fairway Buoys
A fairway lateral buoy is red and white. If you are traveling upstream, you should keep this buoy on your port side (left side). Likewise, if you are traveling downstream, you should keep the buoy on your port side again.
If lit, the light will be white. If not lit, the top will be rounded. The white is usually retroreflective.
The fairway buoy is used to mark entrances to a channel, channel centers, or landfall locations.
Port Hand Buoys
The port hand buoy marks out the port side (left side) of a passageway or channel. It might also mark out that you must remain to the port side of danger when traveling upstream. Either way, stay to the left of this buoy when traveling upstream.
The port hand buoy is colored green. If it has a light, it will also be green in color. With no light on top, the top will be flat. The paint is usually retroreflective as well. The topmark will be a cylinder if equipped. This will appear to be a square from any angle along the horizon when looking at the buoy from a distance.
Sometimes, these buoys have a letter and odd number(s) on them. If posted, this number corresponds to a nautical chart location.
Starboard Hand Buoys
A Starboard hand buoy is red in color. When equipped, it will have a red light. If unequipped with a light, it will have a top mark that is in the shape of a cone. This way, it will appear as a triangle from all directions along the horizontal when viewed from a distance. The red color is typically retroreflective as well.
Sometimes, these buoys are marked with a letter and a number. If this is the case, the number will be an even number or number. These numbers would correspond to a nautical map location as well.
The starboard buoy marks out the starboard side (right side) of a channel or passageway when traveling upstream. It can also mark out a danger that you have to stay on the left side of, making the buoy (or danger in this case) to be on your right or starboard side.
Isolated Danger Buoys
The Isolated Danger Buoy marks out dangers that must be avoided. Usually this is some kind of submerged danger like rocks or a shipwreck. This buoy is typically mounted directly above, sometimes right on the obstacle itself. The isolated danger buoy also tells us that the danger which it marks has navigable water all around it in all directions.
The buoy for isolated danger is black, with a single red band horizontally in the middle. There are two spherical topmarks, also in black. Sometimes, the buoy is marked with a letter or letters but not with numbers. This letter will correspond to a noted danger on a nautical chart. That is where you will typically find information about the size and depth of the danger that the isolated danger buoy is marking.
Port Junction / Bifurcation Buoys
The port junction or bifurcation buoy is green in color (retroreflective) with a single red band horizontally across the midsection of the buoy. The top will be flat. Sometimes, this buoy has a light, and when this is the case, the light will be green in color. The light will flash a sequence as noted in the graphic. When the buoy is equipped with a topmark, it will again be a green cylinder like the port hand buoy. This can be seen from all directions along the horizontal as a square from the distance. Like the isolated danger buoy, this buoy, too, may have markings on it. These will be in the form of a letter or letters, never numbers. These letters will correspond to a junction on your nautical map as well.
This buoy marks where a channel splits (there is a junction) when you go upstream. When you are proceeding to the main channel (preferred channel), this buoy should be kept on your port side (left side).
Starboard Junction / Bifurcation Buoys
The starboard junction or bifurcation buoy is the opposite of the port junction buoy. This buoy is retroreflective red in color. It also has a horizontal band in the middle of the buoy, which is green in color. The top of the buoy will be a cone shape. This will be seen from any direction along the horizontal as a triangle, from a distance that is. When equipped with a topmark, it will also be a cone shape. When equipped with a light, the light will flash a red sequence, as noted in the above graphic.
This buoy can again be lettered, but not numbers. The letters will correspond to a point on your nautical map as well.
As mentioned, this buoy is the opposite of the port junction buoy. When this buoy is in place, it marks a split or junction in the channel when traveling upstream. When the main channel (preferred channel) is desired, you should keep this buoy on your starboard side (right side).
Cardinal Aids Buoys
The cardinal aid buoys are sort of like the isolated danger buoys with one big difference. The cardinal aid buoy tells you which side of the buoy is safe to travel for example. If you have a north cardinal aid buoy, then you would want to travel along the north side of the buoy for safety.
Likewise, if it were any of the other cardinal directions, south, east, or west even, then the direction the buoy marks is the side of the buoy you want to be on.
The cardinal aid buoys are marked in black and yellow and often have a white light. This light flashes a corresponding sequence to let you know what direction it is telling you is safe to pass along.
The following are the four cardinal aid buoys and their corresponding light sequences. Note the special topmarks for each.
North Cardinal Aid Buoy
South Cardinal Aid Buoy
East Cardinal Aid Buoy
West Cardinal Aid Buoy
Special Purpose Buoys
Special Purpose Buoys are those which mark a specific location for a specific danger or purpose. These buoys have no special designated shape. The buoy will sometimes have a light, and if it does, the light will flash yellow in the described sequence. Special Purpose Buoys are typically not labeled, but if they are, they will be letters and not numbers.
Anchorage
The Anchorage Buoy marks out the edge of a designated area where you can anchor your boat. Again, this buoy is yellow retroreflective. The buoy doesn’t have to have a light or a topmark, but when it does, the light will be yellow, and the topmark will be an “x” when equipped. This buoy will have an anchor symbol on it denoting the buoy’s purpose. Just make sure you check your nautical charts for the water depth in the area if you are operating anything other than a flat-bottom boat.
Cautionary
The Cautionary Buoy is always yellow in color and retroreflective. There is no fundamental importance to the buoy’s actual shape, it is simply a cylinder in most cases but does not have to be this shape. The buoy is sometimes equipped with a light that will be yellow in color. Sometimes, the buoy also has a topmark, which would be an “x” topmark. The Buoy may be lettered but is never numbered.
Cautionary Buoys mark a danger. This could be an underwater pipeline, a firing range, a seaplane base, or other area where no through channel exists and boating is not permitted except under circumstances specifically associated with the location, such as a boat used to go out for repairing an underwater pipeline or similar maintenance type of boats. In another word, no general boating traffic is allowed.
Control
Control Buoys are used to note things like speed limits, wash restrictions, and that sort of thing. The restriction is noted in the orange circle. There are also two orange bands, one above and one below the circle. No topmark is used on control buoys, but sometimes they do have a light that flashes in yellow with the same sequence as many other special buoys.
Diving
Just as the name says, this buoy marks out a location where scuba diving or other such diving occurs. Boaters are advised to steer clear of this area to avoid potential accidents that could harm a diver who may be rising from the depths beneath.
The Diving Buoy is often yellow or white, and the shape of the base does not really matter. It is evident as a diving buoy based on the large red square with a white stripe passing across the square diagonally.
These buoys do not have a topmark but sometimes have a yellow light. The light will flash yellow in the same sequence as many other special-purpose buoys, as noted in the graphic above.
Hazard
Hazard Buoys note a hazard such as a shoal or rocks. The type of hazard is often noted inside the orange diamond on the buoy. These buoys do not carry a topmark. They can have a light, though, and this will flash in the customary way of many of the special buoys. If a light is equipped, it will flash in yellow.
The difference between the Isolated Danger Buoy and the Hazard Buoy is that the Isolated Danger Buoy warns of a danger that is otherwise in the middle of or surrounded by navigable waters. The Hazard Buoy typically warns of hazards that may increase with distance, like a rocky shoal jutting out from shore.
Information
An information buoy looks very similar to a control buoy or a hazardous buoy. Again, this buoy has two horizontal orange bars. This buoy also has an orange outline of a square in between the two orange horizontal bars. The square will typically share some form of local information about something like a campsite, marina, or other such location.
The Information Buoy does not carry a topmark. Sometimes, this buoy is also equipped with a flashing yellow light. This light, if equipped, will flash the same yellow sequence as most other special buoys, as noted in the graphic above.
No Trespass / Keep-Out Buoy
The No Trespassing Buoy, or Keep Out Buoy, as some call it, designates an area where boats are prohibited from entering.
This buoy is similar to several other special buoys in a few ways. First, it has two horizontal orange bars across the top half and bottom half of the buoy. Between these is another orange diamond. However, unlike the hazard buoy, this buoy has an orange cross in the center of the orange diamond.
The No Trespassing Buoy has no topmark. Sometimes, however, it is equipped with an orange flashing light. This light will use the same flashing sequence as most other special buoys. See the above graphic for the light sequence.
Mooring
Just as this buoy says, it notes a place of mooring. This is an area where boats may tie off to a dock or other mooring point. There may be other ships moored in this area, so caution and lower speeds are a must.
The Mooring Buoy is typically white in color with an orange cap on the top. This buoy typically also has a topmark in the shape of a sphere and in white rather than the orange of the buoy’s top.
Scientific (ODAS)
The Ocean Data Acquisition System Buoy, or Scientific Buoy, as it is often referred to, is a buoy that collects meteorological data. This buoy might record weather, water temperature, currents, and other such data. Disturbing this buoy is an offense, so don’t try to moor to it or anything like that.
Again, in a retroreflective yellow, this buoy often has a light on it that flashes five times every twenty seconds. This is the only special buoy with its own distinct flashing sequence.
Swimming
The last of the standard special buoys is also the simplest. The Swimming Buoy is commonly just a white retro-reflective buoy with no special markings or topmark. Sometimes, there is a light equipped which is yellow in color and flashes the customary sequence of the majority of standard special buoys. Although, a light is rarely equipped so don’t expect it. These buoys are also not often marked on nautical charts.
You have likely seen these buoys before. Many times, they are circular and connected via a floating rope. This “ropes off” the swimming area, which provides a sort of barrier for the swimmers to stay inside. Boats are not permitted in swimming areas for obvious reasons.
Bibliography
https://aceboater.com/en/buoys
https://www.tc.gc.ca/eng/marinesafety/tp-tp10038-13-ns-bam-lateral-buoys-896.htm
https://en.wikipedia.org/wiki/Buoy#Navigational_buoys
https://dgllmnti.in/assets/upload/download/original/R43-IALA-Maritime-Buoyage-System.pdf
https://www.notmar.gc.ca/list-livre-en.php
https://www.navcen.uscg.gov/pdf/lightLists/LightList%20V1.pdf