Cozumel is about 28 miles long and 10 miles wide. All of the good diving is located on the west side of the island, where the second largest reef in the world exists. This reef starts near Cozumel and continues all the way south to the country of Belize.
We stayed at the Fiesta Americana, an all-inclusive resort located around the middle of the island on the west side near Chankanaab Park. The weather was great the entire time (around 85-90 degrees) and the water temperature was around 81 degrees for diving.
Cozumel is known for its crystal clear, turquoise waters. Hurricane Wilma visited the island in 2005, and the island is still recovering from the aftermath. Because of the hurricane, some of the reefs still had a coating of sand on them.
We dove the Maracaibo Deep, which is one of the most southern dive spots on the island. I personally went to about 160 feet. This area is cool, and you can see the lighthouse at Punta Sur (South Point) nearby.