Our family just returned from Oahu for the first time. We surprised our 9 and 12 year old kids with this tour. My husband and I are both travel agents so we booked this with a third party. Even by doing that, they were very accommodating. We were originally booked for a Saturday morning but we called to switch to Monday morning and it wasn't an issue at all.
The check in process was easy. They have a small shack at the harbour. Be sure to leave plenty of time to get from Honolulu to Haleiwa. It only took us an hour but we left Honolulu at 5:30 am and arrived at 6:30 am for a 7:30 am start.
The staff was very friendly. Our crew was Dave and Reese, and both were a pleasure. There was 10 guests on board so we split into 2 groups (4 and 6). We each had 20 minutes in the cage which was plenty of time. The cage can be a little crowded if you have someone who kicks their legs lots when swimming. We shared the cage with a lady who didn't really pay attention to where she was swimming/kicking. Otherwise, there would have been lots of room for 6 people.
The waves were rough but we took dramamine before arriving and none of us got sick. Unfortunately, three others on board did. We were lucky enough to see roughly 5-7 sharks while we were out there. It was pretty amazing! They just swim around the cage and check things out. I would do this again in a heartbeat. It was definitely the highlight of our family trip.
Other things to note; bring tip money, they provide drinking water, bring a towel, use reef safe sunscreen, bring an underwater camera (or $75 to buy the video), go early in the morning (as early as possible to avoid rougher water)