And a good day to you, Bob! Yes, I still shoot film about half the time underwater, although I must confess it's 95% B+W now.
To the OP, if I'm shooting color film, it's all chromes. My long preference for tropical clear water (wide angle) has been Ektachrome E100G, which really makes the deep blue of the ocean "pop", as long as you're using fill flash. This works very well for me down to about 80', providing the day isn't overcast.
Knowing how the Hawiian islands are prone to clouds, I'd suggest my other wide-angle preference, Fuji ProviaF in ISO 400. It is a bit more contrasty, and the colors aren't quite as saturated to my eye, but hey, you have to pay for the extra two stops somehow.
If you must have print film, I have no suggestions for color, sorry. The last color neg I've shot with any regularity was Fuji Press in 400, and that was quite a while ago.
Have fun, and take a lead bag for the flight!
All the best, James