Without considering oceans, the largest sea in the world is the Philippine Sea, with an area of about 2 million square miles. It borders the Philippines, Japan, the Marianas Islands and Taiwan. If the term "sea" includes oceans, the largest sea is the Pacific Ocean at 64.19 million square miles.
Excluding oceans, the second largest sea in the world is the Coral Sea, with about 1.85 million square miles in area. The Coral Sea is located near Australia and encompasses the Great Barrier Reef. The Arabian Sea, the third largest sea, is located in the Indian Ocean and has an area of 1.49 million square miles.