Close to where the cruise ships stay is Sunset House or Treasure Island Divers. I have dived with both, and they are very nice operations. Bob Soto Divers are also close, but I haven't dived with them.

If you had time to get to the other side of the island, I'd recommend Tortuga Divers.

If you need more info, email me and I will try to help.

Good Luck, Dale