So, there are a number of lakes near Austin but Lake Travis and Town Lake (aka Ladybird Lake) are where most people hang out because they’re the closest to the city.
Lake Travis is the wakeboarding and getting drunk like there’s no tomorrow lake. A part of Lake Travis is named Devil’s Cove (we assume because of the debauchery that takes place). This is where you want to be from mid May until mid September. Stick to Town Lake the rest of the year. Here’s a visual:
Town Lake is more of a kayaking, stand up paddleboarding, and scenic boat ride place — that’s because it runs along the south end of downtown which means good skyline views but no one really swims in it.