I just left Hawaii in December after 38 years. I have been diving for two years. Depending on what you are looking for, there are great dive spots all over the island. If you're going to be there in the summer months then the North Shore is the place to be. Sharks Cove, Three Tables, Fire House are great dive areas and are very easy shore dives. (My favorites) Haleiwa Trench is an awesome night dive, some the of biggest turtles I have ever seen, nestle into the wall for a peaceful nights sleep. I will give you my ex-husbands e-mail address and phone number if your interested in contacting him, he's a really nice guy and would be happy to take you to some of the spots. He also has a boat at his disposal, if the weather isn't cooperating for shore diving. We also have a dive buddy that used to live in Japan for many years, sorta like you, he's a white guy married to a Japanese gal, and now makes a living taking tourists diving. Let me know if you'd like to get in touch with him and I can e-mail you his numbers. I'm a little jealous, I miss Hawaii sooooooo much.