No matter how much you've enjoyed your visit to San Francisco, a last-minute rush to return the rental car before flying out is not the best way to end your stay. While it's only about 16 miles from Union Square to the San Francisco International Airport, a few pointers can save both time and stress. As with any rental car airport return, after dropping the car off passengers should allow extra time for reaching their departure terminal via airport ground transportation.

Getting to the Airport

Driving south on U.S. 101 from the city, take the exit marked San Bruno Avenue. At the top of the ramp, turn left. At the traffic light by the United Airlines Building, turn right on to North McDonnell Road and follow the signs to rental car returns, customer parking. If driving north on U.S. 101, go past the main airport to the exit marked San Bruno Avenue. Turn right at the traffic light on North McDonnell Road and follow the signs to rental car returns, customer parking. When approaching from Interstate 280, take the Interstate 380 East exit at South Airport Boulevard. At the bottom of the ramp, turn right and follow the signs to car rental return and then to customer parking.

Finding Car Rental Returns

Nine rental car companies operate from the San Francisco International Airport Rental Car Center: Alamo, Avis, Budget, Dollar, Enterprise, Fox, Hertz, National and Thrifty. Zipcar also has reserved spaces here. All are accessible 24 hours a day for car and key drop-off and returns. Six additional rental car agencies are located off-airport: Advantage, Airport Van Rental, Firefly, Payless, RelayRides and SIlvercar. These agencies' hours vary, but are generally not 24 hours. Their drop-off location is served by a free Park SFO shuttle service to the Rental Car Center, but must be requested, so allow extra time.

Dropping Off the Car

Take care to remember personal belongings once you have parked and before you lock the car. Some rental car companies have an employee greet you at your car, do a brief inspection and generate your receipt on the spot with a handheld device. When there is no one present, place the completed contract and the keys in the drop box. Matters such as lost and found, vehicle accident reports, email receipts and other queries should be addressed online at the rental company's website when the rental counter is unattended. Check the car's gas indicator beforehand, as you can save money by returning the car with the agreed upon level.

Transportation to the Terminal

At the rental car center, board the free AirTrain Blue Line to the terminals. The fully automated train operates 24 hours a day to all four terminals, parking garages, the SFO Bay Area Rapid Transit Station and back to the Rental Car Center. The train and the stations are wheelchair accessible and each station has elevator service. The AirTrain runs every four to five minutes, except overnight when it runs every 15 minutes. The distance between the Rental Car Center and the departure terminals is approximately 2 miles with a journey time of 10 minutes.