I just got back from a month in Hawaii. Dive Oahu is a good bunch but they dive the same three wrecks and rotate through six different reefs. http://www.reservation.diveoahu.com/ give Kai a call in the shop. She will answer all of you questions. Aaron`s Dive Shop will go anywhere you want and in some cases will pick you up from your hotel if you are staying in Waikiki.http://www.hawaii-scuba.com/ If you ask for Mark or Darren, they are a couple of great guys and they will try to get you to get certified in anything you are not currently certified in. I checked out island divers. They sounded good but I didn`t get a chance to dive with them. I plan on doinga couple of dives with them on my next trip.http://www.oahuscubadiving.com/ Check out all of their websites. there is great snorkeling all over the island. I recommend Hanauma Bay. The North Shore has some great beaches. I did snorkel Honu, Sunset, and Sharks Cove. All great if you want to swim with the turtles.