On our planet oceans are the biggest water bodies, which compose the major mass of the marine-biome. According to scientific-data, they cover approximately 71% of the earth's surface area. So, precisely how many oceans in the world are there and answer is four. Formerly, there were only four officially known oceans in the world. A new ocean was named and declared later by the year 2000, by IHO (the International Hydrographic Organization). This ocean was named as the Southern ocean and it is the fifth one. It extends from the southern-part of the Atlantic Ocean, Pacific Ocean, and Indian Ocean.

A brief explanation of how many oceans in the world are there is taken for discussion. Pacific Ocean is the deepest ocean in the world. The deepest trench in the world the “Marina trench” lies in this ocean. The “Marina trench Challenger Deep” is the deepest part of the ocean. Pacific Ocean is also the largest ocean in the world, expanding over a 65.3 million square miles and covers a huge area. Atlantic Ocean
after the Pacific Ocean is the next in the deepest and largest ocean in the world. It is estimated that 20% of the earth's surface area is occupied by the Atlantic Ocean extending over a 41,100,000 square miles area. Indian Ocean is the third largest ocean on the planet and it covers approximately 20% of the earth's water surface. Southern Ocean also known as the “Antarctic Ocean”, it is newly added in the world ocean list. It surrounds the south-portion of Antarctica continent as the name signifies. Measurement wise, it is the 4th biggest ocean, which covers a larger area than the “Arctic ocean”. However, it is claimed to be the “South Sandwich trench”, measuring a deepness of approximately 7,235 meters. The Arctic Ocean lies in the northern hemisphere and is the smallest of the five oceans. Arctic Ocean depth wise also, comes in the last with its deepest point recorded to be about 5,450 meters. Arctic Ocean is situated in the polar region part of the “Arctic Ocean” remains covered by frost all the year round. Therefore, it is less salty as compared to other oceans. There is only one ocean, as all the five oceans of the world are interconnected to each other. These five oceans are today officially recognized as the deepest and largest oceans of the world.