I had read there were not many places to swim for public access. We had a camper and this was a quick hopeful stop to see the pretty lake everyone talks about. it's the Carribean of the North and it does hold up.
I had read: If you want to hit the sandbar without a boat, wear your swimsuit and park on the shoulder of Crystal Beach Road just north of Torch River Marine (12906 Cherry Ave., Rapid City) and the bridge over Torch River. There's a pocket park with a patch of sand; walk from the shore to the sandbar in chest-deep water.
Thankfully, we were able to park in the lot across from the realty office and we put our suits on. I had bought tubes to inflate in hopes of floating out instead of walking, but when we got there we realized it wasn't allowed to swim in that area (it's a launch). Thankfully, Clear water Rentals had a few kayaks and we asked if they rented by the hour, they did. We were able to get two (our family of 5 fit just fine with my kids being 16, 13, and 11). The coolest part is that they were clear kayaks, so we paddled out and were able to hang out on the sand bar. It was overcast, but still beautiful and very clear water! We were thankful this company was there at the right time, or we wouldn't have been able to do our quick stop!