The Antarctic Ocean, also known as the Southern Ocean (by some, officially: The Southern Ocean), is the fourth largest ocean on Earth and comprises the southernmost waters of the World Ocean. The Antarctic Ocean is generally considered to be below 60° South latitude as it encircles the continent of Antarctica. This ocean comprises just less than 7 percent of the total ocean surface area, and is larger than only the Arctic Ocean. With a size of 8,480,000 square miles (21,960,000 square kilometers) is larger than only the Arctic Ocean.

The maximum depth of the Southern Ocean was surveyed by the Five Deeps Expedition in early February 2019. This maximum depth of 24,390 feet (7,434 meters) was located at coordinates -60.479444, -25.542222 and was visited with the crew submersible DSV Limiting Factor on 03 February 2019.

The Southern Ocean has typical depths of between 13,000 and 16,000 feet (4,000 and 5,000 meters) over most of its extent with only limited areas of shallow water. The greatest depth of the Southern Ocean, at 23,740 feet (7,236 meters) occurs at the southern end of the South Sandwich Trench, at 60°00'S, 024°W. The Antarctic continental shelf appears generally narrow and unusually deep, its edge lying at depths up to 2,600 feet (800 meters), compared to a global mean of 436 feet (133 meters).

Historically, it was James Cook in the 1770s who prove that the World Ocean waters encompassed the southern latitudes of the Earth, and still today, there are some who disagree weather this southern region being considered an ocean, or just the southern limits of the Pacific, Atlantic and Indian Oceans.

However, it was in the year 2000, wheb the International Hydrographic Organization (IHO) finally settled the debate after the full importance of Southern Ocean overturning circulation had been ascertained, and the term Southern Ocean now defines the body of water which lies south of the northern limit of that circulation.

The Southern Ocean, geologically the youngest of the oceans, was formed when Antarctica and South America moved apart, opening the Drake Passage, roughly 30 million years ago. The separation of the continents allowed the formation of the Antarctic Circumpolar Current.

8,480,000 square miles (21,960,000 square kilometers)

17,226,000 cubic miles (71,800,000 cubic kilometers)

13,000 - 16,000 feet (4000 - 5000 meters)

23,740 feet (7.236 meters)

(-60.479444, -25.542222)

28,159 miles (45,317 kilometers)