All of the world's oceans are completely or partially within the Eastern Hemisphere. The Eastern Hemisphere contains all parts of the world east of the Prime Meridian and west of the International Date Line.
The Arctic Ocean surrounds the North Pole and contains the waters of the Arctic Circle. The Southern Ocean contains the waters surrounding Antarctica. Because the boundary of each ocean encircles the globe, approximately half of each ocean is in the Eastern Hemisphere. The Prime Meridian transects the Atlantic Ocean, and the International Date Line transects the Pacific Ocean. The basin of the Indian Ocean lies almost directly between the two longitudes.