Short-term rentals (STRs), commonly referred to as "short-term residential rentals" in San Francisco, are legal but highly regulated. The regulations mandate that the property must be the host's primary residence, where they must reside for at least 275 nights per year. Additionally, hosts can only rent their units for up to 90 nights if they are not present during the rental (un-hosted) and must register with the City of San Francisco to operate legally. STRs primarily thrive in urban apartments, particularly in areas catering more to tourists than business travelers, given the city's vibrant attractions and events. The market is characterized by strong demand from visitors seeking accommodation in close proximity to downtown, the tech sector, and popular sites like the Golden Gate Bridge. The City of San Francisco's Office of Short-Term Rentals oversees the regulation of these rentals, ensuring adherence to local laws and community standards. For comprehensive details on regulations and procedures, you can visit the official websites: San Francisco FAQs on Short-Term Rentals and City of San Francisco short-term rental law.