A couple of weeks ago we went to a national park east of the city for an overnight. We stayed in a ger camp, did some hiking, and did a river rafting trip the next day. The rafting was nice except for a minor scrape (literally) with a tree — the river banks were higher than normal.
Families camped upstream and there more rowdy younger groups of campers as we moved downstream. No one seemed to have bathing suits, and most were comfortable stripping down to their undies to enjoy the water (no swimming, just a few people in where they could walk). Rafting is not a big past time in Mongolia, and I think we were a novelty — we had many greetings from the people on shore as we floated downstream.
The water was very cold and the weather wasn’t warm enough to make up for that (think Barton Springs in November), but that didn’t stop Tom from getting in the water.