This isn't exactly a nudist resort. Harbin Hot Springs is a center devoted to meditation, massage, and soaking in spring-fed pools. It's north of San Francisco, a fairly arduous drive from the Bay area on many winding, twisting roads.
It used to have a large building that housed kitchens, a library, and rooms devoted to all sorts of meditation and massage. It burned down in a fire in 2015, along with some of the on-site rooms available. Much has been rebuilt, but the registration office, a yoga center, and a diner have re-opened in office trailers. When I was there, attendance was strictly limited due to COVID, and masks were required even in the pools. All massages and massage classes have been discontinued until at least June, when the county is expected to relax some of the pandemic preventative measures.
It's clothing optional in any areas not visible from the public road. I'd say that only one person in twenty had any swimwear on in the pools. I camped in a parking lot for campers (other campers had tents set up either in a meadow or on platforms by a creek, but I was in a VW camper). From that area to the pools was a half-mile walk on a well-maintained dirt path. There are also plenty of rooms, for those who don't wish to camp.
I opted not to wear any clothing at all for the entire stay, except for one night when I wore a bathrobe at the pools because it was very chilly. (They recommend wearing a robe because there is a limit to the number of people in each pool, and there is sometimes a wait to get in.)
They have eight pools. Three of them have a restriction of total silence. There's a small 110-117 degrees pool, a larger 95 degree pool, and a small "cold plunge" pool. That arrangement is mirrored in another set of three pools, these allowing quiet conversation. The "hot pool" there was only around 105 degrees when I visited it in the morning. Finally, there's a large 95 degree pool and an even larger pool for swimming laps, which is left unheated. There's ample deck area around the pools for sunbathing, exercising, and simply relaxing with a book. No electronic devices are allowed in the pool area.
The URL for Harbin Hot Springs is here: https://harbin.org/
There's a "sister hot springs" in the Sierras near the Nevada border. It's another natural hot springs site, but the sulfur content of the water is very high, and may be off-putting for people with sensitivity to sulfur (such as me).
Interesting, but sounds kind of restrictive, like a bit of a trip is being pushed. Were you happy with your experience overall?
@ttinnwa All in all, I was. As I mentioned, the ability of the resort to fulfill its aims was severely restricted by both the damage from the fire in 2015 and by the COVID restrictions imposed by Lake County, where the resort is situated. But their main intention, to provide a quiet clothing-optional place for meditation and just "getting away," was still accomplished. It was never designed to be a "resort" as most people define one, with tennis courts, volleyball areas, and like that, but if you don't need those things and are looking for a place to hike nude, bask in a pool or eight, and reconnect with yourself, you won't be disappointed.