Best Oahu dive operation

I'm a new diver going to both Oahu and Kona for 5 days each. Can I get recomendations on the best dive operations there?

I don't know that I can say what operator is "best" since I just returned from my first dive experience on Oahu, but I can tell you that I used Deep Ecology in Haleiwa (on the North Shore, about a 45 min drive from Waikiki). I was pleased with the service they provided. On two of the three days I dove, I was the only one getting the guided tour - just me and the DM/Instructor. I did all shore dives at Firehouse and Shark's Cove, including one night dive. They also run boat dives. They have an 800 number you can call - talk to Pat (shop opens for business at 9am...Hawaii is 3 hours behind West Coast time) or you can fill out a booking request at the web site.

Can't help you with Kona since I haven't done any diving there.

FWIW, Deep Ecology was recommended to me by a local diver.

I can recommend Ocean Concepts on Oahu and Jacks on the Big Island...do their night Manta dive!