Training on business in San Francisco

The best facility in town is the JCC. Not in Union Square but only 2 - 2.5 miles away. A very short bus ride or a nice warm-up walk. I have no idea about using the facility on a short term basis but it will have more than you would ever need in the way of workout options. Nice people too.

I got this advice a few years ago- call the hotel concierge. They got me into a private club and even reserved a lane for me at the time I wanted to swim (I had never even heard of reserving a lane- but it's a thing in SF). It was great since I was very limited on time and had an open water race that weekend I wanted to be ready for.

I rented a bike from Golden Gate Rides and it was a pretty nice bike. I rode all the way out to Sausalito and rode up and down the hills just west of there. It was awesome. I had my regular running shoes with me so when I joined a group I was immediately identified as an outsider. As you know, triathletes are pretty hard to drop. You drop off the back in a sprint and just time trial your way back into the group. We can be annoying that way.

Koret Health and Rec Center at University of San Francisco. Great gym facility and up to 16 lanes available for swimming. I noticed some of the spin bikes could be used with SPD clipless. $20/visit. Bring a lock for the locker room.

If you can get away for a bit...run the golden gate bridge. A quick uber/taxi ride from Union Square.

Thanks everyone for all the great advise. It's really helpful!

Some of my all-time favorite business trips were to San Francisco. (And my reasons for saying this have nothing to do with the conferences that I attended.) The highlight was renting a bike downtown, roding across the Golden Gate Bridge to Sausolito and then up and over some hills to get to Muir Woods National Monument.
I wasn't a runner at the time but if I were there now I would want to get outside for some running.
Don