I have fished Oahu that time of year the Ahi are starting to show a bit and wahoo and mahi mahi are about and always lots of cuda. We fish R, S, and T bouys off the shore of Waianae on the north west end of Oahu. There are also Bone Fish about the islands if that's your game. Mostly wadding sight fishing for these bad boys, but well worth it.

I'm looking at being there in mid May to visit the inlaws, cant wait to fish warm water for a change

Good luck!!!