[Myka]

We visited Kauai in April this year. We didn't do any diving, we snorkeled quite a bit though. There are lots of tunnels and caves underwater on Kauai from lava flows. It is some interesting landscape for sure. I'm not sure where the Kai National Park is, but we found the best snorkeling to be at Tunnels Beach at the north end. Btw, if it's raining down south, go to the north end.

If you can, do a helicopter tour! I think this is an absolute must on Kauai since most of the island can only be seen by air. Most of it is inaccessible by vehicle or foot. We used Blue Hawaiian Helicopters and thought they did a good tour.