We did this last year with our 4 year old son. Aulani outsources this to Hawaii nautical. So if you book through aulani you pay a lot more. You get a ukulele player on board for the return trip I believe but outside of that you get the same experience. So we booked through Hawaii nautical. The pick you up from aulani, on whatever day you signed up for, in a large shuttle bus similar to a rental car shuttle but with their decals on he outside and all. The drive to their marina was about 20-30 minutes. You board the nice catamaran and sail south I believe to a lovely spot where they guarantee you see dolphins. We did, a large group of spinners. Then you get briefed on how to use the snorkel gear, they have kid sizes, and you snorkel for awhile in a wonderful spot that is super colorful. My 4 year old got cold quickly and we headed back to lay on the nets and waited until lunch was served. After lunch you sail back. It was really nice and I thought the price was fair. It was our big splurge experience as well. Also highly recommend Waimea falls if you have a rental car. The walk is amazing the to safe waterfall with lifeguards you get to swim in, although a bit cold as well. And quite inexpensive. Have a great time!!!