SFO airport guide

San Francisco SFO Airport Guide: Terminals, BART and Tips

San Francisco International Airport, San Francisco, United States: terminals, getting to the city, security, lounges and connections.

Quick answer: SFO has three domestic terminals (Harvey Milk Terminal 1, Terminal 2 and Terminal 3) and the International Terminal, which has two boarding areas, A and G. United uses Terminal 3 for domestic flights and Boarding Area G for most of its international flights. The free AirTrain links every terminal, the garages and the Rental Car Center around the clock, and BART runs from the International Terminal to downtown San Francisco in about 30 minutes.

Facts checked November 2026. Schedules and entry rules change, so confirm with the airline and the official government site before you travel.

SFO at a glance

Terminals	Harvey Milk Terminal 1 (B and C gates), Terminal 2 (D gates), Terminal 3 (E and F gates), International Terminal (A and G gates)
United	Terminal 3 for domestic flights, International Terminal G for most international flights
Between terminals	Free AirTrain, 24 hours; the domestic gates are also linked behind security
Rail to the city	BART from the International Terminal, about 30 minutes to downtown San Francisco
Caltrain	BART or SamTrans to Millbrae, then Caltrain down the Peninsula
Rideshare	Domestic terminals: top level of the parking garages; International Terminal: departures level island

Which airlines use which SFO terminal

Harvey Milk Terminal 1 has Boarding Areas B and C. As of November 2026, Alaska Airlines, American Airlines, Southwest and JetBlue board in B, and Delta boards in C. Terminal 2 (Boarding Area D) is used by Air Canada and Breeze, among others. Check with the airline, because assignments change.

Terminal 3 (Boarding Areas E and F) is United's domestic base. Part of Terminal 3 is being rebuilt, and some United domestic flights have moved to Terminal 2 during the work, so check your boarding pass for the terminal.

The International Terminal has two separate boarding areas. Boarding Area G is used by United's long-haul flights and most Star Alliance airlines. Boarding Area A is used by most other international airlines, including most SkyTeam and oneworld carriers, and by some low-cost airlines for international flights.

Assignments move as construction goes on. Check the terminal and gate on your boarding pass or in the airline app on the day you fly, and especially before an early flight.

The International Terminal: A gates vs G gates

When people search for the SFO international terminal, the key detail is that it has two security checkpoints, one for Boarding Area A and one for Boarding Area G. Check-in for both is in the same large departures hall, but you need to know which side your gate is on before you join a security line.

Arriving from abroad, all passengers clear US immigration and customs in the International Terminal. Global Entry kiosks and the Mobile Passport Control app can shorten the wait for US citizens.

The SFO Museum's Aviation Museum and Library is on Level 3 of the International Terminal, next to Boarding Area A, before security, and is free to visit. Art exhibits run through the terminals on both sides of security.

AirTrain, BART and Caltrain

The AirTrain is free and runs 24 hours a day. The Red Line loops through all terminals, the International Terminal garages and the BART station. The Blue Line also stops at the Rental Car Center and long-term parking. Some sections close overnight for maintenance, with buses in their place.

BART leaves from a station in the International Terminal, next to Garage G. The ride to downtown San Francisco stations such as Powell Street and Embarcadero takes about 30 minutes. BART also runs to Millbrae, where you can change to Caltrain for Palo Alto and San Jose.

BART does not run all night. For a very late arrival, check the last train before you land, or plan on a taxi or rideshare.

Taxis, rideshare and driving

At the domestic terminals, Uber and Lyft pickups are on the top level of the parking garages: go up to Level 3 of the terminal and cross the bridge. At the International Terminal, rideshare pickups are on the island on the departures level.

Taxis wait at marked stands on the arrivals level outside each terminal. The drive to downtown San Francisco takes about 25 to 30 minutes without traffic, and longer at rush hour on US-101.

If you are being picked up, the airport's cell phone waiting lot lets drivers wait free until you call from the curb.

Connecting at SFO

The domestic terminals are linked behind security, so a domestic-to-domestic connection between Terminals 1, 2 and 3 usually means a walk rather than a new security check.

Boarding Areas A and G are not joined directly to each other behind security. Moving between them airside means walking through the domestic terminals; on the landside you can take the AirTrain and clear security again.

Flying in from abroad and connecting to a domestic flight, you clear immigration and customs at SFO, collect your checked bags, hand them back at the connection bag drop and clear security again. Allow more time than the minimum connection your airline will sell, especially on a separate ticket.

Lounges by terminal

United runs a Polaris lounge near Gate G1 for long-haul business passengers, and United Clubs in Terminal 3 and in Boarding Area G. The American Express Centurion Lounge is in Terminal 3, near Gate F2.

In Harvey Milk Terminal 1 there is an Alaska Lounge and an American Admirals Club in Boarding Area B, and a Delta Sky Club in Boarding Area C. Several international airlines, including British Airways, Emirates and Air France-KLM, run their own lounges in Boarding Area A.

Entry depends on your ticket, status or card, and most lounges admit you only within a few hours of departure. Check the lounge rules before you go.

How early to arrive and practical tips

Airlines generally advise arriving 2 hours before a domestic flight and 3 hours before an international one. Fog can cause morning delays at SFO, because the two parallel runways cannot always be used side by side in low cloud, so leave slack on tight connections on foggy days.

TSA PreCheck is available, and CLEAR operates at several checkpoints. Free Wi-Fi covers the terminals, and SFO has yoga rooms in the domestic terminals for a quiet break.

Frequently asked questions

What terminal is the international terminal at SFO?

The International Terminal is its own building with two boarding areas, A and G, each with its own security checkpoint. United and most Star Alliance airlines use G; most other international airlines use A.

Which terminal is United at SFO?

Terminal 3 for domestic flights and International Terminal G for most international flights. Some United domestic flights have moved to Terminal 2 during construction, so check your boarding pass.

Which terminal is Delta at SFO?

As of November 2026, Delta boards in Harvey Milk Terminal 1, Boarding Area C. Check your boarding pass, because assignments can change.

Is the AirTrain free at SFO?

Yes. The AirTrain is free and runs 24 hours, linking all terminals, the garages, the BART station and the Rental Car Center.

How long does BART take from SFO to downtown San Francisco?

About 30 minutes from the station in the International Terminal. BART does not run all night, so check the last train for a late arrival.

Can I walk between terminals at SFO without going through security again?

Between the domestic terminals, yes. Boarding Areas A and G are not directly connected airside, so plan extra time if you move between them.

Where do Uber and Lyft pick up at SFO?

At the domestic terminals, on the top level of the parking garages. At the International Terminal, on the island on the departures level.