If there's no sand, dock to climb down into the water from is nice for swimming. Let's you avoid coming out with muck all over your feet. Just be sure your swimmers know "no diving."
During swimming season, I cram half an 8 foot aluminum extension ladder into the bottom from the dock and tie it off to a dock post with bungees. This has proven to be nice and stable for getting in and out of the water, and comes out easy before the ice forms in Winter.