Concur with @Streydog and @deepsea21 regarding the accommodations. Here is the link to the Suites Colonial. I will be staying there myself over Xmas and New Year.
Suites Colonial Cozumel
I think someone mentioned it already, but Blue XT Sea has very good pricing on diving, they run 6 pack boats with no more than 6 divers and one divemaster. Their boat leaves at 8am from the small dock (known as the Aldora dock/pier) directly across the street from the breakfast at Casa Mexicana. Very convenient and gives you a little more time for breakfast or to sleep in. Blue XT~Sea Diving - Cozumel Scuba Diving - Blue XT~Sea Diving
Suites Colonial Cozumel
I think someone mentioned it already, but Blue XT Sea has very good pricing on diving, they run 6 pack boats with no more than 6 divers and one divemaster. Their boat leaves at 8am from the small dock (known as the Aldora dock/pier) directly across the street from the breakfast at Casa Mexicana. Very convenient and gives you a little more time for breakfast or to sleep in. Blue XT~Sea Diving - Cozumel Scuba Diving - Blue XT~Sea Diving