For those who aren’t familiar with this area of San Francisco, there are at least two excellent spa opportunities if hot water, sauna and possibly a massage are your thing.
The Kabuki Hot Springs is in the same Japan Town complex as the hotel. It has a Japanese-style bath area (just one, so it’s men on Thursday and Saturday, women on Friday and Sunday.) You can also get a shiatsu massage, and personal rooms with spa and massage are available for both sexes on all days. http://www.kabukisprings.com/
There is a Korean Spa across Geary Street, the Imperial Day Spa. http://www.imperialdayspa.com. This has a similar open spa area with sauna, steam, and a wonderful room with a heated stone floor. You can get a massage or a scrub, and if you want to go full monty there is something called the “pineapple.”