Just returned from our first trip to AK on July 3 and loved it. If you arrive on a Saturday at 10:30AM, expect to be stuck in customs for at least an hour or two. They act live they're surprised that a couple planes full of people just arrived on a Saturday morning. The queues form, and then they decide to turn on their computers and log in. Once you're through the airport, all good. AK has somebody there with a sign to greet you. Have a $3 local beer outside customs while you wait for all the AK customers to clear customs. Our favorite beer was Salva Vida. You can take it with you on the bus to the resort (about 20-30 minutes away). Check in and head to the dive shop on the pier, where they'll assign your locker and dive boat (you'll be on the same boat with the same crew all week if you go Saturday-to-Saturday).
Dive boats go out 3 times a day - 8:30AM, 10:30AM and 2:30PM. Excellent dive operation - very efficient. Most dive sites are 5 to 10 minutes from the resort. Night dives go on Tuesdays and Thursdays. The shark dive is optional for $115 per person and AWESOME. It goes once or twice a week depending on demand. Very well organized and safe. It's a 30 minute dive to 70 feet. You'll spend 15 or 20 minutes swimming with Grey reef sharks, 5 minutes watching them feed, and 5 minutes looking for shark teeth. The day we went, there were 15 sharks.
They have 18 dolphins in a natural pen on the property - you can snorkel with them for $100 but you can't dive with them. However, sometimes you can luck upon wild dolphins - we did on our way back from the shark dive - captain stopped the boat and we all jumped in and swam with about 50 wild dolphins!
BRING BUG SPRAY! No skeeters but the no-see-ums will get you if you walk on the sand without protection. Not nearly as bad as some people report - just spray your legs and feet, especially if you are staying out on the key.
We are definitely going back...