The four oceans on Earth are the Pacific, Atlantic, Indian and Arctic. These four oceans make up about 70 percent of the planet. The southern portions of the former three oceans merge at the Antarctic region, but this area of water is not generally considered an ocean.
The Pacific Ocean flows between Asia and Australia on the west and North and South America on the east. The Atlantic Ocean lies between the Americas and Europe and Africa. Both the Pacific and Atlantic Oceans have northern and southern regions with differing circulating patterns. Africa is the western boundary of the Indian Ocean and Australia forms its eastern boundary. The Indian Ocean lies mainly in the southern hemisphere. The Arctic Ocean lies near the North Pole. The land regions of Alaska, Canada, Greenland, Russia and Scandinavia almost completely surround the Arctic Ocean.