For an international-to-domestic connection at San Francisco International Airport (SFO) in 2026, you should allow a minimum of 2 to 3 hours. Even if your flight is on a single ticket, you must go through the full federal inspection process: this involves clearing U.S. Customs and Border Protection (Immigration), collecting your checked bags from the international carousel, re-checking them at the "Connecting Flights" desk, and then clearing TSA security again to enter the domestic terminal. If you have Global Entry and TSA PreCheck, you can often complete this process in 60 to 90 minutes. However, SFO is a massive hub, and if your arrival is delayed or if you arrive during the "noon rush" when most trans-Pacific flights land, the lines can be long. In 2026, all SFO terminals are connected airside via the "AirTrain" or walkways, which makes moving between Terminal G (International) and Terminal 3 (United) or Terminal 2 (Delta/Alaska) relatively fast once you are past security. If your layover is under 90 minutes, it is considered "tight," and you should alert a flight attendant or gate agent to see if they can help expedite your exit from the aircraft.