Most take some walking to get to if yo want natual hot springs.

The easiest and one of the best is Deep Creek Hot Springs.

I believe that there are several old threads on this tribe that describe how to get there (there is more than one route). The trail from the Bowen Ranch is the easiest and quickest.

There are other "developed" hot springs such as Jacumba (east of San Diego) and Glen Ivy along with a couple of others. It really depends on what you want, the amount of time you have, and your budget. Ping me off-list if you like.

SoCal has a few tubs. Nothing as good as the Sierra Nevada or NorCal regions tho.

Jacumba, CA is a small town east of San Diego with rustic resort & amenities.
Campground Agua Caliente on S2, in Southern Anza Borrego Desert, From Los Angeles, the Sierra Nevada may have better options that SoCal. And of course, Deep Creek near Arrowhead.

BUT my suggestion: The beautiful Lower Kern River is 3 hour drive fro LA & you can find my favorite (my local hot tub) REMINGTON, located near Borel Rd exit on Old Kern Cyn Rd. After you find Hobo Camp & Miracle Hot Springs (which is mostly closed), keep driving westbound slowly, looking for the hidden dirt parking lot. Camping is very limited.

It takes a but of patience to reach this the first time & a half mile steep down hill trail will greet you, but you will soak with the river in full view, the coolest locals, as well as regional & international travelers, that know about this secret spot. I created a page on it here -
www.totalescape.com/active/l...gton.html

I go at least once per month, for a night or a few.

This may be too late to help Heather, but....

I'd second the recommendations for Deep Creek, especially if you're just looking for a day trip. Plus there's the bonus of the cool stream adjacent to the hot pools.

For a night or two of camping, my favorites are in the Saline Valley (about a six-hour drive from L.A.) and Guadalupe Canyon (in Baja, south of Mexicali). I just returned from Saline two days ago.

I've heard a lot about Remington, and would endorse anywhere Danamite recommends, sight-unseen, but have never been myself.

Feel free to PM me for any more specifics.