San Francisco airport (SFO) has a Centurion Lounge exclusively for American Express Platinum cardholders and above. Simply present your valid Platinum Card, a boarding pass showing a confirmed reservation for same-day travel, and an ID. You may also bring two additional guests free of charge and additional guests can be added on for $50 each.

Location: Access from the post-security in Terminal 3 or International Terminal G. If you are flying out of another terminal, you may be able to use your boarding pass to enter through T3 security, subject to approval by the TSA agent. After visiting the Lounge, you will need to exit through security, take the AirTrain or walk to your terminal and re-enter through security.
Hours: 5am-11pm
Size: 8,171 sq. ft.
Dining: Full breakfast, lunch, and dinner menus designed by James Beard Award-winning chef Daniel Patterson, plus a Napa Valley tasting area. Morning menu items include lemon verbena corn cakes and a chard and pine nut quiche. For lunch or dinner, try the zucchini and burrata salad and the braised tofu with seaweed.
Amenities: Take advantage of the Lounge’s luxurious Shower Suite, Premium Bar, Open Kitchen, Family Room, Semi-Private Workspaces, High-Speed Wi-Fi, and Computer Bar.

Source: Departures