We took a tour on a bat boat when we visited Austin last May. The boat took us up and down the shoreline of a lake in downtown Austin. Just before sunset, we hovered under the Congress Street bridge and could hear the bats cooing. The bats began to come out from under the bridge in a trickle, but the flow grew greater and greater. For 15 minutes we sat and watched as the streams of bats joined up and darkened the sky. It was the most amazing thing I've seen in a long time.
My children were 7 and 2 1/2 at the time, and both enjoyed the experience immensely. Several friends have since expressed a dislike of bats when hearing of our adventure, but the bats do not come anywhere near you. It is perfectly safe. They are coming out to hunt insects for dinner, not to bother people.
It is also possible to see the bats from the sidewalk of the Congress Street bridge or from the neighboring shoreline, but I would recommend getting on one of the boats your first time. The tour guide gave us some really interesting information and had a dead bat that we could see up close.
