Navigation Warning Buoy

Green buoys
Often termed "starboard hand buoys", these mark the channel's right side when moving towards the shore or heading upstream. They may flash a green light. Example: Entering a harbor, you'd keep these on your right.

Red buoys
Otherwise known as "port hand buoys", they signify the left side of a channel from the open sea or when traveling upstream. Typically, they may flash a red light. Example: Navigating a river mouth from the sea, these should be on your left.

Red and green banded buoys
Indicating the center of a channel, the topmost band denotes which side to pass on. They may have a combination of red and green lights.

Yellow buoys
Special purpose buoys, they can represent various scenarios like a military exercise zone or a seaplane base. Light rhythm can vary based on the specific purpose, but is always different from standardized light marks.

Orange and white buoys
These regulatory markers, usually square or diamond-shaped, convey information like speed limits or specific warnings. Their light rhythms can vary based on the specific regulations they indicate.

Weather buoys
An integral part of marine safety and research, weather buoys are specialized devices floating on the ocean's surface, primarily designed to collect and transmit valuable atmospheric and oceanographic data. These buoys help sailors, researchers, and meteorologists understand weather conditions, ocean currents, and other marine-related phenomena.

Tidal buoys
Tidal Buoys are a subset of oceanographic buoys specifically designed to monitor and provide data about tidal movements and sea level changes. Given the immense significance of tides in marine navigation, fishing, coastal management, and even renewable energy extraction, tidal buoys play a crucial role in various marine sectors.

Diving buoys
These are used to indicate that diving operations are currently taking place in the area, and often shown as a white buoy with a red flag (or the Alpha flag, a blue and white flag, in international waters). The red flag has a diagonal white stripe from the top left to the bottom right. Vessels are advised to stay clear in a radius of 100 meters of the area or proceed with extreme caution when they see a diving buoy.

Grounding buoys or shoal buoys
These buoys indicate the presence of shallow waters or hazards beneath the surface, such as sandbanks or rock formations. They might have a variety of appearances depending on the region, but they often have specific markings or colors to indicate the nature of the hazard. These are critical for the safety of vessels, ensuring they don't run aground or hit submerged hazards. If you see one or more of those, make sure you stay out of that zone and check the surroundings with your depth radar, fish finder or a rope with a weight and knots for the meters (the traditional way).

Isolated danger buoys
Used to mark small, isolated dangers such as a single rock or wreck. These buoys are black with one or more horizontal red bands. They might also have an accompanying light. They inform mariners of hazards in an area that is otherwise safe to navigate around.

Restricted area buoys
Indicate areas where boating is temporarily restricted. It could be for environmental protection, swimming areas, or any other reason. Varies by region. In some areas, these buoys might be white with a black band and carry a specific symbol indicating the type of restriction. Helps in protecting sensitive marine areas, swimmers, or specific zones from vessel traffic. Also often used to mark fish farms.

Cable and pipeline buoys
They mark the locations of underwater pipelines or cables. Typically yellow in international waters with the letter “C” on them. Prevents vessels from anchoring in areas where they might damage submerged infrastructure.