San Francisco International (SFO): The Complete Layover Guide

Four terminals arranged in a ring: Harvey Milk Terminal 1, Terminal 2, Terminal 3, and the International Terminal with its two boarding areas, A and G. Since June 2024 the ring is complete behind security: International A connects to Terminal 1, then 2, then 3, then International G, all airside. Connecting passengers can ignore the AirTrain entirely, which is good, because the AirTrain is landside and riding it means a trip back through a checkpoint. It runs 24 hours with trains as often as every 4 minutes, useful for the Grand Hyatt and the rental car center.

Security and immigration

Domestic connections rarely involve security at all now. Arriving international passengers clear immigration and customs, then reclear security, standard for the US; typical passport control waits run about 5 minutes for US citizens and 7 to 9 for visitors, longer when the morning transatlantic bank lands between 6 and 9am. The wifi, by the way, is genuinely fast and free with no cap, which softens most delays.

The lounge landscape

The United Polaris Lounge in International G is the prize, entry by qualifying international premium cabin ticket only. The big 2025 change: the Amex Centurion Lounge left Terminal 3 for the duration of its modernization, with a temporary location in Terminal 2 near gate D12, open 5am to 11pm. Priority Pass opens the Golden Gate Lounge, the Virgin Atlantic Clubhouse, and the China Airlines Lounge. United Clubs, a Delta Sky Club, an Admirals Club, and an Alaska Lounge round it out. Full table in the SFO lounge directory.

Sleeping at SFO

Open all night, tolerable rather than welcoming. There are no dedicated rest zones; the padded benches in the International Terminal are the default. Freshen Up, landside near the Boarding Area G entrance, runs 24 hours with showers and paid nap rooms, including an overnight block. The Grand Hyatt is one free AirTrain stop away. Details in the SFO sleeping guide.

Getting to the city

BART leaves from the International Terminal, landside, and reaches downtown in about 30 minutes for roughly 11 dollars. Trains run from about 5am on weekdays to around midnight. On a layover of 6 hours or more, the Embarcadero and the Ferry Building are a realistic round trip. SFO also fills shorter layovers better than most airports: free SFO Museum exhibitions, the Aviation Museum in the International hall, and yoga rooms in Terminals 2 and 3.

The small print that helps

The museum program is not a gimmick. SFO Museum is the first accredited museum inside an international airport, and the rotating cases between gates reward a slow walk. The Aviation Museum and Library in the International Terminal main hall is free, needs no ticket, and sits before security, which makes it one of the few good ways to spend a long landside wait in America.

The AirTrain runs 24 hours on its Red and Blue lines, which matters at 3am when the Grand Hyatt or the rental car center is the destination; trains come as often as every 4 minutes. The wifi is unlimited and quick enough to embarrass most hotel networks. Freshen Up, landside near Boarding Area G, keeps its showers running around the clock, and a shower after a red eye buys more alertness than a third coffee.

Harvey Milk Terminal 1 is the showpiece of the rebuild, and its airside connector is what finally closed the walkway ring in June 2024. If you can choose where to sit, the newer piers are calmer, and the yoga room near gate E6 in Terminal 3 opens from 4am to 11pm.

Can I change terminals at SFO without going through security again?

Yes. Since June 2024 all four terminals connect behind security in a complete ring of airside walkways: International A to Terminal 1 to Terminal 2 to Terminal 3 to International G. The AirTrain is landside, so riding it means reclearing security; walk airside instead when connecting.

Where is the Centurion Lounge at SFO now?

The Terminal 3 Centurion Lounge is closed through 2027 for the terminal modernization. A temporary Centurion Lounge operates in Terminal 2 near gate D12, open 5am to 11pm daily. With the airside walkway ring you can reach it from any terminal without leaving security.

Can you sleep overnight at SFO?

The airport stays open 24 hours but offers no dedicated sleep zones. Travelers use the padded seating in the International Terminal and quiet gate areas. Freshen Up, landside near the Boarding Area G entrance, runs 24 hours with showers and paid nap rooms including an overnight option. The Grand Hyatt at SFO is the real bed, one AirTrain stop away.

How do I get from SFO to downtown San Francisco?

BART from the station in the International Terminal reaches downtown stops like Powell and Embarcadero in about 30 minutes for roughly 11 dollars one way. Trains run from about 5am weekdays until around midnight. It beats a rideshare on both price and predictability for a layover run.

Which lounges can I use with Priority Pass at SFO?

The Golden Gate Lounge, the Virgin Atlantic Clubhouse, and the China Airlines Lounge are the Priority Pass options at SFO. Capacity rules and hours shift, so check the app the day you fly. The United Polaris Lounge is not accessible with any card; it requires a qualifying international premium cabin ticket.

What can I do for free on an SFO layover?

SFO Museum runs free rotating exhibitions across the terminals, and the Aviation Museum and Library in the International Terminal main hall is free before security. Yoga rooms sit in Terminal 2 and Terminal 3 near gate E6. Trained therapy dogs from the Wag Brigade roam the terminals most weeks.