Aquarena is not open to the general diving public.
The lake itself is protected under both the Federal Endangered Species act and the Texas Antiquities Act. Diving in the lake itself requires a science diver certification from the Texas River Systems Institute at Aquarena (2 day class/test @$220.00). After you get the certification, the diving is strictly controlled under a volunteer program to maintain the Lake and the Springs. You need to request a dive permit at least 72 hours in advance, and once granted, you have to restrict your dive to the Lake area and maintenance task assigned. Diving without a certification or a permit is a serious violation of both the federal and state statutes, and if you get caught by an officer who’s having a bad day, the fines can be HUGE.
The “practice” area is open to the public only for schedules OW certification classes or other occasional special events. You can’t dive in the practice area unless you’re registered for one of the classes or special events.
It’s well worth it to get the certification. The lake is a gorgeous, crystal clear gem right in the heart of Texas. Its chock full of fish species and being able to get close up to the actual springs is amazing. It was the best money I’ve spent on diving hands down, and I’m there as often as I can get there. Once you’re certified, getting a permit is easy as long as you follow the rules. I generally make it down there several times a month.