The Pacific Ocean is the world's major ocean, with an magnitude of about 63,800,000 square miles. Locality: Among the Arctic and the Southern Ocean to the south. The Mariana Trench has a extreme deepness of 36,070 feet (11,000 meters) and an average depth of 3,970 meters. Capacity: 669,880,000 cubic kilometers. The shoreline measures 135,663 kilometers. - Islands: In excess of 25,000 islands, as well as the Philippines and the island landform of Australia .