While staying at the St. Regis Princeville, my husband and I used the childcare service run by Princeville Chaperones (www.princeville.biz 808-651-3452), for babysitting and the Young Voyagers (kids) Club. The kids went snorkeling, and of course Capt. Paul was so awesome. The kids loved the attentiveness of Capt. Paul and couldn't stop talking about all the things they learned. They talked more about Capt. Paul and snorkeling than they did about anything else on the trip!.
We even took an "adult" snorkel trip since he's a marine biologist, which included a walk through the native plant garden to see how native plants related to animals in an ancient story of creation.
We highly recommend this company on north shore in Princeville. They made us feel welcome and like one of the locals!