The dock was opened by Edward VII and Queen Alexandra in 1907. At the time the coal industry in south Wales made Cardiff one of the busiest ports in the world.
Queen Alexandra dock was once the main artery through which south Wales exported coal during its mining heyday. Today the dock continues to support the region's economy.
By 1913, 10.7m tonnes of coal were exported through Cardiff, and much of it was sent out in the holds of locally-owned steamers.
A number of events have been organised to celebrate the 100th anniversary of the dock, including a photographic exhibition, which will feature all these shots and more.
The exhibition is at Associated British Ports Cardiff, Queen Alexandra House.
The Treaty of Versaille after World War I and the great depression of the late 1920s and '30s had a profound effect on Cardiff's ports.
By 1932, coal exports fell to 5m tonnes and the port never recovered. Despite intense activity during World War II, coal exports declined and finally ceased in 1964.
As well as the photographic exhibition, ABP Cardiff is holding an open day at the port on Saturday, 22 September, where the public can view life at the port in the modern day.