A water park, but not with slides and giant wave pools...well, wait a minute, it DOES have the second largest wave pool this planet has to offer. Located south of Miami and 20 miles east of Everglades National Park, Biscayne National Park offers one the chance to swim in a giant fish tank. Most of the park is underwater—and it's there that you need to go to see it (or take the glass bottom boat tour for a glimpse). Admission is free. Boat trips are extra.
We chose to dive Biscayne upon recommendation from divers living in Florida that assured us it was one of the top reefs in the state. It's patch reef in this area, and the captain picks the spots you dive. Ours was a high wave day—the dive was almost canceled because of it—but we got two dives in, getting a glimpse of part of the outer reef.
Our dive experiences away from home thus far have been limited to Hawaii and the St. Lawrence River. There's no comparison to be made from the tropical waters of Florida and the fresh water of the St. Lawrence, but comparing Hawaii, I can say we saw many more coral varieties in Florida and many more fish in quantity and variety in Hawaii. Both were enjoyable, and for those of us living inland and needing a "dive fix" on a trip, it was worth going to since we were already there. I'm not sure I would have made a special dive "trip" just to this spot, as I suspect other Caribbean areas would top it. However, there's more cost with those, so...
To dive Biscayne, the Park's Concessionaire offers trips on Saturday and Sunday only—and requires an 8 person minimum to make the trip. The cost for a two tank dive is $57 including tanks and weights, but not rental equipment (available if needed). The dives we went on were both shallow (max depth of 31' on our computer). All the set up of your equipment is self-done. The captain was friendly—gave a quick overview of the spot and gave you a time to be back on the boat (be sure you have a watch). On shore there are restrooms, but no hot showers. On the boat, there are no facilites.
Overall, we had an enjoyable time and I'd be interested in returning to see other areas of Biscayne underwater, especially on some of the glass-clear days this place is famous for.
For those that don't dive, snorkel trips are offered daily, as are glass bottom boat trips. The visitor's center has some nice exhibits and has three different movies on the park. Admission is free, the view is nice, and picnic lunches there seem popular. There is a small store, but don't expect much. If you want lunch, bring it—otherwise, head to Homestead for the nearest restaurant choices.