Homestead Resort in Midway Utah is a cozy place, we stayed the weekend and reserved a swimming / snorkeling session in the crater. It was a pleasant 90 degree water swim, a nice contrast to the snowfall outside. We reserved about an hour, maybe 50 minutes to swim which was plenty. There were SCUBA divers below as well.
https://www.youtube.com/watch?v=e1lxf048d7c
