I know that you are looking for something other than the Caribbean, but you might want to take a look at the special being offered by all 3 of the all-inclusive Tibbetts Family Dive Resort on Little Cayman, Cayman Brac, Grand Cayman, see the link below.
The special runs from mid-November to mid-January and includes free Nitrox and free Nitrox certification. It also includes lodgings, food, diving, transfers, taxes, and hotel service charges. I suggest the Little Cayman Beach Resort, the boats aren't small but they're not cattle boats and valet diving is provided. It's a small resort (about 40 rooms) and you can walk to nearby Blossom Village, but it is much quieter than Roatan's West End.
You are likely to see some sharks but not many but plenty of groupers, turtles, eels, rays, other tropicals, and beautiful coral walls.
2 dives in the morning but no shore diving, but you can add-on a 1 tank afternoon boat dive for an additional fee. The food is buffet style but good.
You have to fly to Grand Cayman and then take a half-hour flight to Little Cayman.
We are going back there in the fall to celebrate our 40th Anniversary!
Free Diving, Nitrox, and Nitrox Certification*
