Searching Southwest, I found seats departing Nashville BNA on Friday, August 3, returning from San Francisco SFO on Wednesday, August 8.
Other dates are available for travel through mid-November, with a 14-day advance purchase required.
An excellent fare on Southwest, which is currently much cheaper than other airlines on this route. Southwest includes two free checked bags and has no change fees making this an even better deal compared to other airlines, which charge hefty fees.
Need a room in San Francisco? Here is what is available for the above dates on Hotelwatchdog.