Which is the deepest natural harbor in the world?

Port Jackson in Sydney, Australia, is the deepest natural harbor in the world. It has a perimeter of approximate 200 miles (321.9 km) and in some spots it’s 100 feet (30.48 meters) deep. It is also home to 550 species of fish, making it one of the most diverse harbors in the world.

It is better known by the name of Sydney Harbor in many places outside Australia with famous photos of the Sydney Opera House and the Sydney Harbor Bridge.

When Australia was first explored by Europeans, this harbor was the first settlement site. Governor Arthur Phillip established the colony that would later become Sydney on the south side of the harbor in 1788. In his first dispatch from the colony back to England in May 1788, Governor Phillip wrote, “...we had the satisfaction of finding the finest harbor in the world, in which a thousand sail of the line may ride in the most perfect security...”

Prior to the colony’s establishment however, the first recorded European discovery of Sydney Harbor was by Lieutenant James Cook in 1770.

A harbor is a body of water where ships, boats, and barges can be docked. A natural harbor is a landform where a section of a body of water is protected and it is deep enough to allow anchorage.