Call Mike at Dive Kauai in Kapa'a. You need to do the Niihau SCUBA boat trip (if you have a PADI license).We did one of the boat trips to snorkel on the North Shore. Most beautiful place on Earth that I've seen. My in-laws have a timeshare in Princeville and one on the big island's west shore.
Amen brother!
Diving Niihau is insane. Most SCUBA divers would rank it in the top ten in the world.
I maxxed out at 120 feet. You don't think about iPhones at that depth.