One of the activities on Maui that seemed to appeal to people of all ages in our group (from young child to older adult) was the Atlantis Submarine Ride. There is also an Atlantis Submarine Ride on Oahu, but the Maui one departs from Lahaina Harbor in west Maui. A boat takes passengers to the site where the submarine emerges from the previous submarine trip so that the riders can see what it looks like upon emerging. After the riders from the previous trip disembark from the submarine and step onto the boat, the riders for the next ride get onto the submarine and the submarine descends.
The submarine takes its occupants on a small cruise underwater (reaching depths of roughly 100 feet) and around an artificial reef arising from the intentionally sunken Carthaginian. The submarine captain does a nice job of attempting to maneuver the trip so that occupants on both sides of the submarine can see interesting schools of fish and other sights from their own side of the submarine. I felt like the cruise itself wa appropriate in its duration and it seemed popular with passengers of all ages.
I was very impressed with the organization and people running Atlantis Submarines Maui. They were courteous, professional, helpful, and made it fun for everyone. When I was pre-ordering the tickets online before we traveled to Hawaii, one of their representatives called me at home to make sure that I hadn't overbooked when I arranged for tickets for my own family and the family of my brother with the same number of family members and same last name. As I was explaining the two orders, the woman who called realized that I qualified for a generous discount that I had not been aware of and offered to apply it to our purchase. I found the service related to the excursion itself to be similarly helpful.
The photographs I have included in this post do not do the views of the underwater marine life and formations justice. Although there are a few things about the submarine cruise that appeal to children, it is still an interesting ride with fascinating views for the adults. For those of us who don't scuba dive, it's a great opportunity to see different things in water this deep than we can see when we snorkel.