The "must know" info on scuba in GC, Coz, and Costa Maya

[Sun and Fun]

My DH and brother-in-law are planning on scuba diving when we go on our cruise next Saturday to Grand Cayman, Costa Maya, Cozumel and Belize. We have a full day in Belize, but can anyone give me the important need to knows for the other three ports?

 

1. Where is the best place to rent the equipment (not bringing anything with)?

 

2. Where is the best place to dive at the three location - actually we know about Grand Cayman - been there before - but what about Cozumel and Costa Maya?

 

3. Any other important stuff they should know?

 

Thanks!