the first largest is definitely The Great Barrier Reef. I'm pretty sure that the second largest is The Belize Barrier Reef. And for the third largest, I'm not sure, but I think it's the Red Sea Coral Reef.
Yes, Its the largest coral reef in the world located in Queenland, Australia The Great Barrier Reef, the world's largest coral reef, lies a short distance off the northeast coast and extends for over 2,300 kilometers (1,240 mi).
The Great Barrier Reef is the largest coral reef in the world. It extends 2300 km down the coast of Queensland, Australia. However, it is not the only coral reef in Australia. On the west coast, off Exmouth, is Ningaloo Reef, another impressive coral reef.