Cardinal buoys indicate a hazard by reference to the four cardinal directions (points) of the compass: north, east, west, and south. A cardinal buoy indicates that the safest water exists in the direction indicated by the cardinal point (direction) represented by the buoy. They can be in the form of buoys or fixed aids, but are predominantly buoys in Canada.

North Cardinal Buoy – Is positioned so that the safest water lies to the north. The top half of the visible portion is black and the bottom half is yellow. If present, the top mark is two stacked cones, black in colour, both pointing up. If the buoy does not carry a light, it is normally spar (tall and thin) shaped.

South Cardinal Buoy – Is positioned so that the safest water lies to the south. The top half is yellow and the bottom half is black. If present, the top mark is two stacked cones, black in colour, both pointing down. If the buoy does not carry a light, it is normally spar shaped.

East Cardinal Buoy – Is positioned so that the safest water lies to the east. This buoy is black in colour except for a broad horizontal yellow band around its midsection. Its top mark consists of two stacked black cones; the top one pointing up, the bottom one pointing down. If the buoy does not carry a light, it is normally spar shaped.

West Cardinal Buoy – Is positioned so that the safest water is located to the west. This buoy is yellow in colour except for a broad horizontal black band around its midsection. Its top mark consists of two stacked black cones; the top one pointing down, the bottom one pointing up. If the buoy does not carry a light, it is normally spar shaped.