When it's not covered with people for ACL or Blues on the Green, Zilker is a really nice spacious park. However, it really shines with the regular events that occur on it. If traveling in the summer, I'd highly recommend you go to Blues on the Green.
I ran around there each morning and it was spectacular! Even at 6:30 I felt very safe there with plenty of other runners.
We did a lot of things on our trip to Austin and this was a highlight. Open fields, turtle watching on the river and walks along a few paths. A way to relax on a busy vacation.
came here for the 2019 ACL Music Festival, BUT have been here before when no events were at the park. It is a very nice park and really big parks to walk around. I would recommend comming here.
In the summer you can kayak, canoe, swim hike, play frisbee golf, basketball, volleyball and tons of other activities. In the winter many activities still available, but we love walking all around the lake for miles, enjoying how beautiful it is.