The snorkeling in Pupukea (Oahu north shore) is amazing. I’ve yet to do it but supposedly the hammerhead shark dive off of Molokai is bucket list material. You’ll need AOW cert. for that
AFAIK (working on that one myself, right now I’m “just” OW certed...)
I’ve done a few off of Maunalua Beach Park (Koko Craters, Turtle Canyon, etc.) all good. Want to do the Corsair but that’s also an AOW requirement so will have to wait.
I’ve heard from an instructor that the manta ray dive off of the big island is other-worldly. I’m hoping to get over there later this year perhaps...
In general you can’t do too badly in the islands.
Lots of good stuff around.
You’ll need less weighting here than you’re probably used to as well. Warm, salty water...
Look into Airbnb’s (although they’re sorta under attack by the big money hitel industry and often need to be done on the down-low). You’ll save hundreds over the big rip-off resort hotels and get to meet some cool people, usually.