City sightseeing san francisco downtown tour hop on hop off sightseeing bus tour of san francisco with audio commentary your ticket allows you to leave and re board the bus as often as you wish and is valid for 24hours from the time of first boarding the tour lasts around 90 minutes if you stay on the bus but you can take as long as you like at each of the 12 stops your ticket will be valid for 24hours from the time of first use