DC is by prior reservation only - they normally are fully booked for a given day buy about 45 to 60 days in advance - even if you are not doing the dolphin swim portion - park attendance is limited to 1000 per day
Thanks for the reply! I guess we will call and check availability and if it is not open we will go with our back up plan of a boat tour in the gulf and the beach.
If you are still in need of help I do know that if you book and then something happens you can have one complimentary date change. The reservations people are also pretty good about giving you extra changes if something happens like a hurricane or you have a family emergency or something.
Heather