While there is one global interconnected ocean, this massive body of water surrounding all land masses on Earth can be further subdivided based on historical, geographic, and cultural factors.
The number of oceans in the world depends on the perspective.
There are three major oceans: The Pacific, Atlantic, and Indian. In addition, the Arctic and Southern (Antarctic) Oceans make up the two additional oceans. The Southern Ocean is a fairly recent addition (2000) that is not universally recognized by all countries and organizations and has yet to be ratified by the international community (see next section). For example, the U.S. Board on Geographic Names recognizes the Southern Ocean while National Geographic does not.
The animated GIF below shows the names of the world’s oceans based on one global ocean, the three major oceans, the four historic oceans, and the five world oceans.
How are the Ocean Borders and Names Determined?
The International Hydrographic Organization (IHO), which first convened in 1919 (and was originally referred to as the International Hydrographic Bureau (IHB)), is the inter-governmental organization that creates the international agreement of ocean borders and names. The outcomes of each convention are published in the Limits of Oceans and Seas.
IHO (International Hydrographic Organization), 2000. Report of the International Hydrographic Organisation. Working Paper No. 57 (WP 57). 20th Session of the United Nations Group of Experts on Geographical Names, (New York), 17–28 January 2000.