San Francisco (SFO) to Seoul Incheon (ICN) Flights: Nonstops, Flight Time and Entry Rules

Four airlines fly SFO to Incheon nonstop

As of November 2026, four airlines fly between San Francisco and Incheon without a stop. United flies the route twice a day, one departure late in the morning and one close to midnight. Korean Air runs one daily flight that leaves SFO around midday, and Asiana runs one daily flight that leaves just before midnight. Air Premia, a younger Korean airline that started flying from SFO in May 2024, flew the route on several days a week rather than daily through its summer 2026 season, with an afternoon departure that reaches Incheon in the evening; confirm its winter days with the airline. Schedules change with each season, so check the current timetable with the airline before you plan around a departure time.

Several of these flights are sold under two names. United sells seats on the Asiana flight under a United number, Asiana sells seats on both United flights, and Delta sells seats on the Korean Air flight. Asiana is due to leave Star Alliance in mid-December 2026 as it merges into Korean Air, so for travel after that point check whether a United-numbered ticket on the Asiana flight is still offered. The airline that actually operates the aircraft decides your terminal, your check-in desk and your baggage rules, so look for the "operated by" line when you book.

The departure time matters more than it looks. The midday departures land at Incheon in the late afternoon of the next day, which is an easy arrival: you can take the train into Seoul and go to bed at a normal hour. The near-midnight departures land around 5 am, two calendar days after you left. That suits a traveller connecting onward to elsewhere in Asia, but it can leave you in Seoul hours before hotel check-in.

One-stop options and where they connect

With four nonstop carriers there is rarely a reason to connect, but one-stop itineraries do appear in searches, usually on dates when the nonstops are full. The common patterns are a short hop down or up the West Coast to another city with Seoul nonstops, such as Los Angeles (Korean Air) or Seattle (Delta), or a routing through Tokyo on a Japanese carrier. A West Coast connection adds only a short domestic flight, while a Tokyo routing adds a second long leg and usually several hours to the trip. If a connecting fare is close to a nonstop, the nonstop nearly always wins on total time.

Flight time each way and the time difference

Westbound, SFO to ICN is scheduled at roughly 12 hours 45 minutes to 13 hours 10 minutes in the winter 2026/27 timetables (a little less in summer), because the flight heads into the jet stream across the North Pacific. Coming home is much quicker: in the winter 2026/27 timetables, Incheon to San Francisco is scheduled at roughly 10 to 11 hours depending on the airline.

Seoul runs on Korea Standard Time, UTC+9, and Korea does not use daylight saving time. That puts Seoul 17 hours ahead of San Francisco from early November to mid-March and 16 hours ahead while California is on daylight time. In practice you lose a calendar day flying out and gain it back on the way home: an afternoon departure from Incheon often lands at SFO on the morning of the same date.

Airports and terminals

Incheon has two separate passenger terminals, each with its own station on the airport railway, so the terminal is worth checking before you head back to the airport. Going to the wrong one costs time you may not have on a morning departure.

• Terminal 2: Korean Air, Delta and the other SkyTeam airlines. Asiana moved here on January 14, 2026, as part of its integration with Korean Air, so older guides that send Asiana passengers to Terminal 1 are out of date.
• Terminal 1: United and the other Star Alliance airlines, and Air Premia.

Terminal 2 sits further from Seoul than Terminal 1, and the airport train calls at Terminal 1 first on the way out of the city, so allow a few extra minutes if you are heading back to fly Korean Air or Asiana.

If you booked a United number on the Asiana flight, you check in at Asiana's desks in Terminal 2, not United's in Terminal 1.

Entry rules for US citizens

US citizens can visit South Korea without a visa for tourism or short business trips of up to 90 days. Korea normally requires visa-free visitors to hold a K-ETA, its electronic travel authorization, but the United States is on the list of countries temporarily exempted. Korean consulates in the US have announced that this exemption runs from January 1 to December 31, 2026 (Korea time). If your trip arrives in 2027, check the official K-ETA site before you fly, since no further extension had been announced at the time of writing.

While exempt, you complete the free e-Arrival card instead, which can be filed online from three days before you land. Travellers who choose to apply for a K-ETA anyway are spared the separate arrival card. Use only the official government sites for either form, not paid agents.

Getting from Incheon into Seoul

Incheon sits on an island west of the city, so plan on roughly an hour into central Seoul. The AREX airport railway is the simplest option: the express train runs without intermediate stops to Seoul Station in about 43 minutes from Terminal 1 and about 51 minutes from Terminal 2, and the slower all-stop train calls at Gimpo Airport and Hongik University station (useful for Hongdae and Mapo hotels) and connects with the subway. Airport limousine buses run to many parts of the city and can be the easier choice with heavy bags. If you land on one of the 5 am arrivals, check first-train times for the day you arrive.

Best months to go

Spring and autumn are the two strong seasons. Cherry blossoms usually reach Seoul in April, and May is warm and mostly dry. October is the other standout, with mild days, clear skies and autumn colour in the mountains around the city; early November is still crisp and pleasant, but the cold arrives toward the end of the month. The rainy season usually arrives in late June, and July and August are the hottest, most humid and wettest months. January and February are the coldest months, often well below freezing in Seoul, though skies are frequently clear.

Baggage and fare-family notes

The four nonstop airlines package their fares differently, so compare what each fare includes rather than the headline number. United, Korean Air and Asiana each sell several economy fare types, and the cheapest of them can restrict seat selection, changes and refunds. Air Premia's fares are built differently from the full-service carriers', so read what each of its bundles includes before you compare. On a codeshare, the operating airline's baggage rules usually apply at the airport, which is another reason to note who flies the plane. On a 13-hour flight, seat selection matters far more than on a short hop, so check whether it is included before you choose the cheapest option.

Booking tips for this route

• Choose the departure by arrival time: the midday flights land in the late afternoon, the midnight flights at dawn.
• Book the operating airline's own flight number when you can, so changes and delays are handled by one airline.
• Check the Incheon terminal on your return, especially if you fly Asiana or a codeshare.
• Compare against nearby departures too: see all flights from San Francisco, every guide to Seoul Incheon, or the Seattle to Seoul route if you can start further north.