Quick Summary

  • Primary Update: San Francisco International Airport (SFO) features continuous post-security airside connector walkways linking Harvey Milk Terminal 1, Terminal 2, Terminal 3, and International Terminal Boarding Area G, alongside an airside bridge connecting Harvey Milk Terminal 1 to International Boarding Area A. Passengers connecting between domestic flights, or transferring from a domestic flight to an outbound international flight, can walk between all gates without exiting the sterile zone or clearing Transportation Security Administration (TSA) checkpoints a second time.
  • Transit Impact: The United States enforces strict non-sterile transit regulations for all arriving international flights. Travelers landing at SFO on overseas inbound flights—including services on Air India, United Airlines, Singapore Airlines, Emirates, Qatar Airways, British Airways, Lufthansa, ANA, and Cathay Pacific—must clear US Customs and Border Protection (CBP) passport control, claim all checked baggage at the International Arrivals hall, pass customs inspection, and redeposit bags at airline transfer belts before re-clearing TSA security to reach onward domestic gates.
  • Traveler Advice: Budget a minimum connection window of 120 to 150 minutes (2 to 2.5 hours) for international-to-domestic transfers requiring border control and baggage re-check. For domestic-to-domestic connections utilizing post-security walkways or the automated landside AirTrain, allocate 45 to 60 minutes depending on whether your departure gate is in an adjacent boarding area or on the opposite side of the terminal horseshoe.

1. Airport Architecture and Terminal Distribution

San Francisco International Airport (IATA: SFO, ICAO: KSFO) is arranged around a central circular roadway and garage complex forming a continuous horseshoe. The passenger terminal complex consists of four main buildings divided into seven distinct boarding areas labeled alphabetically from A through G:

                     SAN FRANCISCO INTERNATIONAL AIRPORT (SFO) TERMINAL MAP

                                 [ NORTH TERMINAL WING ]
                       +------------------------------------------+
                       |     INTERNATIONAL TERMINAL (BOARDING G)  |
                       |       Gates G1 - G14 (Star Alliance)     |
                       +--------------------+---------------------+
                                            | (Airside Connector)
                                            v
                       +------------------------------------------+
                       |               TERMINAL 3                 |
                       |    Concourse E: Gates E1 - E13           |
                       |    Concourse F: Gates F1 - F22 (United)  |
                       +--------------------+---------------------+
                                            | (Airside Connector)
                                            v
                       +------------------------------------------+
                       |               TERMINAL 2                 |
                       |    Concourse D: Gates D1 - D18           |
                       |    (Alaska Airlines, Delta Air Lines)    |
                       +--------------------+---------------------+
                                            | (Airside Connector)
                                            v
                       +------------------------------------------+
                       |         HARVEY MILK TERMINAL 1           |
                       |    Concourse B: Gates B1 - B27           |
                       |    Concourse C: Gates C1 - C11           |
                       |    (American, Southwest, JetBlue)        |
                       +--------------------+---------------------+
                                            | (Airside Connector)
                                            v
                       +------------------------------------------+
                       |     INTERNATIONAL TERMINAL (BOARDING A)  |
                       |    Gates A1 - A15 (oneworld / SkyTeam)   |
                       +------------------------------------------+
                                 [ SOUTH TERMINAL WING ]

Landside Transit: AirTrain Red Line (Terminals Loop) & Blue Line (Terminals + Rental Car Center)
Direct Rail Link: BART Station located inside International Terminal Level 3 (G-Gate Side)

Terminal Breakdown and Airline Allocations

  1. International Terminal (Boarding Area A – Gates A1 to A15): Located on the southern flank of the International Main Hall. Serves primary non-Star Alliance intercontinental carriers, including Air France, British Airways, Cathay Pacific, Emirates, Etihad, Japan Airlines, KLM, Korean Air, Philippine Airlines, Qatar Airways, Virgin Atlantic, and select international low-cost carriers.
  2. Harvey Milk Terminal 1 (Boarding Areas B and C – Gates B1 to B27, C1 to C11): Located immediately south of Terminal 2. Named in honor of the civil rights pioneer, this modern terminal serves American Airlines, JetBlue, Southwest Airlines, Frontier Airlines, Sun Country, and select Alaska Airlines flights.
  3. Terminal 2 (Boarding Area D – Gates D1 to D18): Centrally located along the eastern curve. Operates as a major operational base for Alaska Airlines and Delta Air Lines.
  4. Terminal 3 (Boarding Areas E and F – Gates E1 to E13, F1 to F22): Located on the northern curve. Serves as United Airlines' massive domestic fortress hub, operating mainline domestic transcontinental routes, regional United Express departures, and inter-state trunk routes.
  5. International Terminal (Boarding Area G – Gates G1 to G14): Located on the northern flank of the International Main Hall. Dedicated Star Alliance hub housing United Airlines' international departures, Air India (non-stop widebody routes to Delhi, Mumbai, and Bengaluru), ANA (All Nippon Airways), Asiana Airlines, EVA Air, Lufthansa, Singapore Airlines, SWISS, and TAP Air Portugal.

2. Inter-Terminal Transit Systems: AirTrain vs. Airside Walkways

Passengers navigating transfers at SFO have two distinct routing mechanisms: the automated elevated AirTrain system on the landside, and continuous post-security airside passenger connectors on the sterile side.

SFO TRANSFER SYSTEMS ROUTING & TIME COMPARISON
Transfer Route       | Transit Mode       | Route Type          | Average Duration | Security Req.

T3 (United) to       | Airside Connector  | Secure walking path | 4 - 8 minutes    | No rescreen
Int'l Boarding G     | corridor           |                     |                  |

T2 (Delta/Alaska) to | Airside Connector  | Secure walking path | 6 - 10 minutes   | No rescreen
T3 (United)          | corridor           |                     |                  |

T1 (Harvey Milk) to  | Airside Connector  | Secure walking path | 5 - 9 minutes    | No rescreen
T2 (Concourse D)     | corridor           |                     |                  |

T1 (Harvey Milk) to  | Airside Connector  | Secure walking path | 7 - 12 minutes   | No rescreen
Int'l Boarding A     | corridor           |                     |                  |

Int'l Boarding A to  | AirTrain Red Line  | Landside APM train  | 6 - 8 minutes    | Must clear
Int'l Boarding G     | or Blue Line       | (departs every 3m)  | + TSA queue      | TSA at G

Int'l Boarding A to  | Airside Connector  | Secure walking path | 22 - 32 minutes  | No rescreen
Int'l Boarding G     | (full horseshoe)   | (via T1, T2, T3)    | (1.4 miles)      |

Any Terminal to      | AirTrain Blue Line | Landside APM train  | 10 - 18 minutes  | Landside
Rental Car Center    | (Blue Line ONLY)   | (departs every 3m)  |                  | destination

Any Terminal to      | AirTrain Red Line  | Landside APM train  | 3 - 9 minutes    | Landside
BART Rail Station    | or Blue Line       | to Garage G / BART  |                  | integration

The AirTrain System (Landside)

The SFO AirTrain is a fully automated people mover (APM) running on elevated guide-ways 24 hours a day, 365 days a year. It operates entirely on the pre-security (landside) public level. Riding the AirTrain is completely free.

  • Red Line: Operates a clockwise loop serving all terminal complexes: International Terminal A, Harvey Milk Terminal 1, Terminal 2, Terminal 3, International Terminal G, and Domestic Parking Garages. The Red Line does not travel to the Rental Car Center or Long-Term Parking.
  • Blue Line: Follows the same terminal horseshoe loop as the Red Line (serving International A, T1, T2, T3, International G) but extends outward along the airport roadway corridor to stop at West Field Road, the SFO Rental Car Center, the Grand Hyatt at SFO hotel station, and the Long-Term Parking facilities.
  • Station Locations: In each terminal, AirTrain stations are located on Level 4. Elevators and escalators connect Level 4 directly to Level 3 (Ticketing/Departures) and Level 2 (Arrivals/Baggage Claim).
  • Service Frequency: Trains depart every 3 to 5 minutes around the clock.

The Post-Security Airside Connector Network

Historically, passengers transferring between airlines at SFO were forced to exit through security, ride the AirTrain, and endure lengthy TSA screening lines at their connecting terminal. SFO has eliminated this friction through modern architectural connections:

  • Terminal 2 to Terminal 3 Connector: A wide, climate-controlled corridor links Concourse D (Terminal 2) with Concourse E/F (Terminal 3). Walking between gate D18 and gate E1 takes approximately 4 to 6 minutes.
  • Terminal 3 to International Boarding Area G Connector: Located at the rotunda of Concourse F, a dedicated airside bridge connects directly into the secure departures area of International Boarding Area G. This allows United domestic passengers arriving at Terminal 3 to walk straight to Air India, Lufthansa, ANA, or United international gates without touching a security checkpoint.
  • Harvey Milk Terminal 1 to Terminal 2 Connector: Seamlessly joins Concourse C (Terminal 1) to Concourse D (Terminal 2), enabling passengers flying American Airlines, Southwest, Delta, or Alaska to walk between terminals airside.
  • Harvey Milk Terminal 1 to International Boarding Area A Connector: Provides a secure airside pathway linking Concourse B to International Boarding Area A. Passengers connecting from domestic carriers to oneworld, SkyTeam, or foreign carriers departing from A can transfer without leaving security.

Caution Regarding Boarding Area A to Boarding Area G Transfers: While all terminals are now technically linked post-security around the perimeter horseshoe (A to T1 to T2 to T3 to G), the walking distance between Boarding Area A and Boarding Area G spans approximately 1.4 miles (2.2 kilometers). For passengers holding TSA PreCheck or CLEAR, exiting to the landside, taking the AirTrain Red Line from Station A to Station G (a 5-minute ride), and clearing security at Concourse G is frequently faster than walking the entire airside horseshoe.

3. Step-by-Step Connection Procedures

Your exact transfer sequence depends on whether your itinerary involves pure domestic segments, an outbound international journey, or an arriving overseas flight.

SFO FLIGHT CONNECTION SCENARIOS & STEP SEQUENCES
SCENARIO A: DOMESTIC TO DOMESTIC (SINGLE OR INTERLINE TICKET)
1. Deplane at arrival concourse. Check electronic Flight Information Display (FIDS) screens.
2. Follow "All Gates" and overhead directional signage toward your departure concourse.
3. Walk through the airside connector corridors (T1 <-> T2 <-> T3).
4. Arrive at departure gate. No security screening or baggage collection required.
SCENARIO B: DOMESTIC TO INTERNATIONAL DEPARTURE
1. Deplane at domestic terminal. Confirm international departure boarding area (A vs. G).
2. If connecting T3 to Boarding Area G: Walk airside via Concourse F connector (5-8 min).
3. If connecting T1 to Boarding Area A: Walk airside via Concourse B connector (7-10 min).
4. If connecting T3/T2 to Boarding Area A: Either walk full airside loop or take AirTrain Red
Line landside and clear TSA checkpoint at International Concourse A.
5. Present passport and boarding pass at the international boarding gate prior to boarding cut-off.
SCENARIO C: INTERNATIONAL ARRIVAL TO DOMESTIC CONNECTION (MANDATORY US BORDER CLEARANCE)
1. Disembark aircraft; follow green "Arrivals / US Customs" corridors down to the FIS hall.
2. Clear US Customs and Border Protection (CBP) passport control (Global Entry / MPC / standard).
3. Retrieve ALL checked luggage from the International Arrivals baggage carousels.
4. Clear CBP customs exit checkpoint with all personal belongings and checked baggage.
5. Turn immediately toward the dedicated Airline Baggage Re-Check belts outside customs doors.
6. Hand luggage to airline agent (United / Delta / American / Alaska re-check desks).
7. Ascend escalators to Level 4 (AirTrain) or walk to onward terminal TSA checkpoint.
8. Clear TSA passenger security screening at onward departure terminal. Proceed to boarding gate.
SCENARIO D: INTERNATIONAL TO INTERNATIONAL TRANSIT (NON-STERILE TRANSIT MANDATE)
1. Disembark overseas flight; proceed directly into CBP border control hall.
2. Present valid US entry visa or approved ESTA (no sterile airside international transit in USA).
3. Claim all checked baggage from the International carousel. Clear customs exit.
4. Re-check luggage at airline transfer desk or re-check counter.
5. Proceed to onward international departure boarding area (A or G) and clear full TSA screening.

Detailed Breakdown: International Inbound to Domestic Onward

Because the United States does not maintain sterile transit zones, international passengers landing at SFO must navigate the Federal Inspection Services (FIS) process regardless of whether their final destination is within the US or abroad:

  1. Border Clearance: Follow the enclosed elevated corridors directly to the International Arrivals Hall. Passengers with biometric passports and an active Global Entry membership can proceed to the dedicated facial-recognition kiosks. Travelers using the official US Customs Mobile Passport Control (MPC) application should follow signs for the MPC designated queue, which moves substantially faster than the standard non-citizen visa line. Indian passport holders with valid US B1/B2, F1, H-1B, or L-1 visas clear through standard CBP inspection booths unless registered for Global Entry or eligible MPC pathways.
  2. Mandatory Luggage Retrieval: Even if your baggage claim tag displays your ultimate destination (e.g., Chicago O'Hare, New York JFK, Seattle, or London), federal regulations require you to personally pick up every checked item from the arrivals carousel. Luggage carts in the customs hall at SFO are complimentary.
  3. Customs Exit and Baggage Re-Check Belts: After collecting your bags, exit through the customs declaration checkpoint. Immediately beyond the double exit doors in both Boarding Area A and Boarding Area G arrivals lobbies, you will find staffed Connecting Flights Baggage Re-Check Desks.
    • If your onward flight was issued on the same ticket or interline booking, an agent will scan your existing bag tags and place your luggage onto the automated transfer conveyor belt.
    • If you are traveling on separate tickets with unrelated carriers (for example, arriving on an international carrier and connecting on Southwest or Frontier without an interline agreement), you cannot use the re-check belts. You must carry your luggage onto the AirTrain to your departure airline's ticketing hall on Level 3 and check in as an originating passenger.
  4. Re-Entering the Sterile Concourse: Once your bags are surrendered at the re-check belt, exit into the public arrivals lobby. Take the escalators up to the departures level. If connecting to a flight departing from Terminal 2 or Terminal 3, you can either take the AirTrain Red Line or walk across the terminal connector bridges. You must then complete standard TSA passenger and carry-on screening.

4. Minimum Connection Times (MCT) and Transfer Matrix

The official Minimum Connection Time (MCT) published by airlines represents the absolute baseline required to legally issue a single ticket. In practice, terminal walking distances, customs processing surges, and TSA queues require realistic buffers.

SFO MINIMUM CONNECTION TIME (MCT) REFERENCE MATRIX
Connection Type          | Official Airline   | Recommended Buffer | Peak Traffic Notes
                         | Baseline (MCT)     | (Realistic)        |

Domestic to Domestic     | 40 minutes         | 50 - 65 minutes    | Simple airside walk within
(Same Terminal)          |                    |                    | T1, T2, or T3.

Domestic to Domestic     | 50 minutes         | 65 - 80 minutes    | Walking between T1 and T3
(Different Terminals)    |                    |                    | requires 12 - 16 minutes.

Domestic to              | 60 minutes         | 75 - 90 minutes    | Boarding gates close 15 - 20
International Outbound   |                    |                    | minutes before scheduled out.

International to         | 90 minutes         | 120 - 150 minutes  | Peak arrival banks from Asia
Domestic (Single Ticket) |                    |                    | & Europe create heavy lines.

International to         | 90 minutes         | 120 - 150 minutes  | Requires full CBP clearance,
International Transit    |                    |                    | bag re-check, TSA rescreen.

Separate Ticket Transfer | Not Protected      | 180 - 210 minutes  | Missed flights forfeit fare;
(Any Carrier)            | (Airlines flag NA) | (3 to 3.5 hours)   | bag check-in cutoffs apply.

Peak Arrival Banks at SFO

SFO experiences two severe international arrival congestion windows daily:

  • Midday European and Asian Transpacific Bank (11:30 AM to 3:30 PM): Massive influx of widebody flights arriving from London Heathrow, Frankfurt, Paris CDG, Tokyo Narita/Haneda, Seoul Incheon, Taipei, and Hong Kong. Customs waiting times for non-registered travelers can stretch to 50–75 minutes.
  • Evening Transpacific and South Asian Bank (6:30 PM to 9:30 PM): Non-stop widebody arrivals from Delhi, Mumbai, Bengaluru, Singapore, Manila, Sydney, and Auckland. The FIS hall operates at peak capacity; passengers with onward connections departing before 10:30 PM should possess Global Entry, MPC, or at least 150 minutes of scheduled transfer cushion.

5. Security Screening, PreCheck, CLEAR, and Priority Channels

Every passenger re-entering the sterile concourses after international arrival—or transferring between terminals via landside AirTrain—must pass through TSA screening. Understanding checkpoint distribution minimizes transfer delays:

SFO TSA SECURITY CHECKPOINTS & EXPEDITED LANES
Checkpoint Location| Operating Hours  | TSA PreCheck  | CLEAR Lanes   | Airside Access

Int'l Terminal A   | 04:30 - 01:00    | Yes (Dedicated| Yes           | Gates A1 - A15, links to
Checkpoint         |                  | lane)         |               | Harvey Milk Terminal 1

Int'l Terminal G   | 04:30 - 01:00    | Yes (Dedicated| Yes           | Gates G1 - G14, links to
Checkpoint         |                  | lane)         |               | Terminal 3 (Concourse F)

Harvey Milk T1     | 03:30 - 00:30    | Yes           | Yes           | Gates B1 - B27, C1 - C11,
Checkpoint B / C   |                  |               |               | links to T2 & Int'l A

Terminal 2         | 04:00 - 00:00    | Yes           | Yes           | Gates D1 - D18, links to
Concourse D        |                  |               |               | T1 and T3

Terminal 3         | 03:30 - 00:30    | Yes           | Yes           | Gates E1 - E13, F1 - F22,
Checkpoint F / E   |                  |               |               | links to Int'l G & T2

Strategic Re-Screening Advice

If you have completed baggage re-check outside International Boarding Area G and the main Concourse G TSA checkpoint shows an extensive queue, you are not strictly bound to clear at Checkpoint G. Because Terminal 3 is connected airside to Boarding Area G, you can walk landside across to Terminal 3 (Concourse F checkpoint), clear TSA there, and walk across the post-security connector bridge directly into Boarding Area G. Checkpoint waiting times are displayed on digital screens across all terminal ticketing lobbies.

6. Ground Transportation, BART Rail, and Baggage Storage

Connecting travelers with extended layovers (exceeding 4 to 6 hours) frequently leave the airport to explore downtown San Francisco, the Embarcadero, or Silicon Valley.

SFO GROUND TRANSIT CONNECTIONS & LAYOVER TRAVEL
Service              | Station Location   | Route / Destination| Transit Time     | Typical Fare

BART (Bay Area Rapid | Int'l Terminal     | Direct to Powell,  | 28 - 32 minutes  | $10.50 -
Transit)             | Level 3 (G-side)   | Montgomery, Embarc.| to Downtown SF   | $11.50

SamTrans Public Bus  | Curbside T2, T3,   | Route 292, 398     | 45 - 65 minutes  | $2.25 -
(San Mateo Transit)  | Int'l Terminal     | to SF Transbay / PA| to San Francisco | $4.50

AirTrain to Rental   | Level 4 all terms  | Direct to Rental   | 10 - 15 minutes  | Free
Car Center           | (Blue Line ONLY)   | Car Facility       |                  |

App-Based Rides      | Domestic Garages   | San Francisco /    | 25 - 45 minutes  | $38.00 -
(Uber / Lyft)        | Level 5; Int'l Lot | San Jose / Palo Alto| (traffic depend.)| $65.00

Riding BART into San Francisco

The SFO BART station is integrated directly inside the International Terminal on Level 3 (Boarding Area G side).

  • If arriving at Terminal 1, Terminal 2, Terminal 3, or International Boarding Area A, take the AirTrain Red Line or Blue Line to the Garage G / BART Station stop.
  • BART trains depart approximately every 15 to 20 minutes on weekdays and weekends, terminating in downtown San Francisco, downtown Oakland, Richmond, and Antioch.
  • Passengers can tap directly at fare gates using contactless credit cards, debit cards, Apple Pay, or Google Wallet via the digital Clipper card system.

Luggage Storage for Layovers

Travelers planning an off-airport layover excursion who have not checked their luggage through can store bags securely at the Airport Travel Agency, located in the International Terminal Main Hall (pre-security, departures level near the Boarding Area G entrance). Rates range from $15 to $35 per 24-hour period per bag depending on luggage dimensions.

7. Transit Amenities, Lounges, and Layover Essentials

For passengers remaining on airport property during a layover, SFO offers extensive amenities:

Airline Lounges

  • United Polaris Lounge (International Terminal G): Restricted strictly to long-haul Star Alliance international business and first-class travelers. Features private daybeds, a full sit-down à la carte dining room, and 8 luxury shower suites.
  • United Clubs: Located in Terminal 3 (Concourse E near gate E4, Concourse F near gate F11) and International Terminal G near gate G6. Accessible via Star Alliance Gold status, United Club membership, or one-time passes.
  • American Airlines Admirals Club: Located in Harvey Milk Terminal 1 (near gate B3).
  • Delta Sky Club: Located in Terminal 2 (Concourse D near gate D1). Features an outdoor Sky Deck overlooking runway operations.
  • The Centurion Lounge (American Express): Located in Terminal 3 (mezzanine level adjacent to Gate F1/F2). Accessible to eligible Amex Platinum and Centurion cardholders departing from any terminal via the airside connector network.
  • Air France / Golden Gate Lounge / British Airways Galleries: Located in International Boarding Area A, serving SkyTeam, oneworld, and priority pass partners during designated windows.

Showers and Quiet Rest Areas

  • Freshen Up! (International Terminal Main Hall, pre-security): Offers private rental shower stalls, toiletries, ironing facilities, and under-bed luggage storage.
  • Quiet Rooms and Yoga Rooms: SFO provides complimentary dedicated Yoga Rooms located post-security in Terminal 2 (Concourse D) and Terminal 3 (Concourse E). A Christian Science Reading Room and interfaith reflection room are located in the International Terminal pre-security hall.
  • On-Airport Hotel: The Grand Hyatt at SFO is directly integrated into the AirTrain network. Passengers take the Blue Line directly to the hotel's dedicated elevated station without stepping foot outdoors. Day-use rooms and overnight accommodations are available.

8. Practical Traveler Logistics Guide

Navigating a transfer at SFO requires executing the following practical checklist:

SFO CONNECTION LOGISTICS CHECKLIST
✓1. VERIFY TERMINAL ASSIGNMENT:
Review your onward boarding pass or airline mobile app. Note whether your departure gate
begins with A, B, C, D, E, F, or G. Concourse letters directly correspond to terminal wings.
✓2. DETERMINE SECURE VS. LANDSIDE ROUTING:
•If transferring between B, C, D, E, F, and G: Stay AIRSIDE. Follow terminal connector signs.
•If transferring between A and G: Evaluate queue times. Walking airside takes 25-30 minutes;
AirTrain Red Line takes 6 minutes plus TSA re-screening.
✓3. INTERNATIONAL ARRIVALS: DOWNLOAD MOBILE PASSPORT CONTROL (MPC):
Download the official CBP MPC app on iOS/Android before departing your overseas origin.
Submit arrival details upon touchdown at SFO to bypass standard immigration queues.
✓4. SURRENDER LUGGAGE AT DEDICATED RE-CHECK:
Never carry through-tagged baggage up to the main departure ticketing hall unless connecting
on an unpartnered low-cost carrier. Drop bags at the re-check belt right outside customs.
✓5. MONITOR BOARDING CUTOFFS:
US domestic flights close jet bridge doors strictly 10 to 15 minutes before departure.
International long-haul departures close boarding doors 15 to 20 minutes prior to pushback.

9. Frequently Asked Questions

Can I transfer between terminals at SFO without clearing security again?

Yes, for the vast majority of connections. SFO features connected airside post-security pedestrian corridors linking Harvey Milk Terminal 1 (Concourses B and C), Terminal 2 (Concourse D), Terminal 3 (Concourses E and F), and International Boarding Area G, as well as an airside link between Terminal 1 and International Boarding Area A. You can walk between all gates airside without reclearing TSA, except when arriving from an inbound international flight requiring mandatory CBP customs clearance.

Does the AirTrain operate airside or landside?

The SFO AirTrain operates strictly landside (pre-security) on Level 4 of each terminal. If you exit the sterile concourse to ride the AirTrain, you must clear TSA security screening to re-enter any gate area.

What is the difference between the AirTrain Red Line and Blue Line?

The Red Line loops clockwise exclusively between the passenger terminals and domestic garages. The Blue Line serves all passenger terminals plus West Field Road, the Rental Car Center, the Grand Hyatt hotel, and Long-Term Parking. If you are only transferring between terminals or connecting to BART, both lines are equally viable. If heading to rental cars, you must board the Blue Line.

Does SFO have sterile international-to-international transit?

No. The United States government requires all arriving international passengers to clear US Customs and Border Protection inspection, collect all checked baggage, and hold valid US entry documentation (a valid US visa or approved ESTA), even if connecting immediately to an onward international flight to another country.

Where do I re-check bags after clearing US customs at SFO?

Dedicated airline baggage re-check desks are situated immediately outside the double exit doors of the International Arrivals Federal Inspection Services (FIS) hall in both Boarding Area A and Boarding Area G. If your bags are tagged through on a single booking, simply hand them to the airline transfer agents at these counters before heading to your departure concourse.

How do I transfer from Terminal 3 (United) to International Boarding Area G?

Walk through the airside connector corridor located near Gate F1/F2 in Terminal 3. It leads directly into the central rotunda of International Boarding Area G in approximately 4 to 6 minutes. There is no security rescreening required along this route.

How do I get to the SFO BART station from the domestic terminals?

Take the automated AirTrain (either the Red Line or the Blue Line) from Level 4 of your domestic arrival terminal to the Garage G / BART Station stop. The train entrance opens directly into Level 3 of the International Terminal, adjacent to the BART turnstiles.