The best dog park in Austin (in my opinion). Not the most convenient park to reach, but the isle is doggy heaven.
Its actually a small peninsula on the lake rather than an island, but its a nice place for people to relax as much as it's a dog park.
Usually fairly busy. I have never had a bad experience with people or their pooches here. Most are kept on a leash.
Some of the more "advanced" trained dogs will be catching frisbees and tennis balls in acrobatic fashion, otherwise most are enjoying the lake/ sunshine.