Prince Shoal Light, Federal heritage lighthouse in Tadoussac, Canada

Prince Shoal Light is a 25.3-metre lighthouse built in 1964 on a dangerous shoal in the St. Lawrence River, about 7 km east of Tadoussac, Quebec. Its cylindrical tower rises from a concrete-filled steel caisson shaped like an hourglass, which acts as both icebreaker and breakwater. The tower is painted in horizontal red and white bands, and its flat roof serves as a helicopter landing pad.

A lightship marked the shoal from at least 1860; the Prince Shoal No. 7 served from 1905 to 1956, followed by Lightship No. 20 and No. 4. The permanent pillar lighthouse was built in 1961 to designs by J.V.L. Cosmo and V. Podreye of the Canadian Department of Transport, with construction supervised by the Canadian Coast Guard, and completed in 1964. It was among the first Canadian sites to test automated lighting equipment and was designated a recognized federal heritage building in 2008.

The lighthouse is nicknamed "la Toupie" (the spinning top) for its hourglass-shaped base. It marks a safe channel at the mouth of the Saguenay, a stretch often covered in morning fog. Its design belongs to Quebec's fourth generation of lighthouses, using steel caissons and automated lights, and it appeared on a Canada Post stamp issued in 1984-1985.

The tower sits in open water and cannot be reached on foot, but it is clearly visible from the shores of the St. Lawrence near Tadoussac. A boat tour is the best way to get a closer look, and several local options pass near it.

On 25 December 1966, a 36-hour storm tore the steel door from the base and flooded the living quarters, forcing keepers Claude Fraser, Ivanhoé Gagnon and Roger Lagacé into the machinery room. No rescue was possible until the storm ended the next day, when a helicopter evacuated them. The tower held, but its light had stopped working.