I was able to find seats departing San Francisco SFO on Sunday, October 28, returning from San Jose SJO on Sunday, November 4. Flights connect in Panama City PTY.
Other dates are available for travel from October 28 through December 12.
An excellent fare on a great airline. Copa includes two free checked bags on all fares.
Need a room in San Jose, Costa Rica? Here's what's available for the above dates on Hotelwatchdog.