I've lived on the largest ocean, the Pacific, for virtually all my life.  I'm now on my longest cruise, across the Pacific Ocean from Sydney to Honolulu.  Almost 71% of the Earth's surface is completely covered by water, representing 96.5% of the water on this planet. There were once seven seas.  These became  five oceans. #1  Pacific Ocean Area:60,060,700 square miles. Average depth:  13,215 feet. Greatest depth:  Mariana Trench 36,198 feet. Has 25,000 islands. Is home to 50% of the world's ocean waters, although  another source  says 46.6%. Is the scene of the most nuclear bomb tests.  The Marshall Islands are more radioactive in some regions than Chernobyl. #2  Atlantic Ocean Area:  41,105,000 square miles. Average depth:  12,880 feet. Greatest depth:  Puerto Rico Trench 30,246 feet. #3  Indian Ocean Area:  26,469,500 square miles. Average depth:  13,002 feet. Greatest depth:  Sunda Trench 24,46...