San Francisco International Airport (SFO) is a major hub for United Airlines, with the Star Alliance carrier operating services to destinations across the world. Among United Airlines’ longest routes from San Francisco are Auckland (AKL), Manila (MNL), Melbourne (MEL), Shanghai (PVG), and Sydney (SYD).
When it comes to domestic routes, United Airlines serves most major US cities from San Francisco International Airport, including plenty of transcontinental routes and routes to the Hawaiian islands. Using data from Cirium, an aviation analytics company, what are United Airlines’ ten busiest domestic routes from San Francisco International Airport in January 2025?
10
San Francisco (SFO) – Seattle (SEA)
160 flights
In January 2025, United Airlines will operate 160 flights in each direction between San Francisco International Airport (SFO) and Seattle-Tacoma International Airport (SEA), making it the carrier’s tenth-busiest domestic route from San Francisco.
Photo: Vincenzo Pace | Simple Flying
United Airlines goes head-to-head with both Alaska Airlines and Delta Air Lines on this popular route. Last year, San Francisco was the sixth-busiest domestic destination from Seattle-Tacoma International Airport, with more than 771,000 passengers per year, behind the following five destinations:
- Anchorage (ANC) – 1,017,000 passengers
- Los Angeles (LAX) – 1,006,000 passengers
- Las Vegas (LAS) – 966,000 passengers
- Phoenix (PHX) – 956,000 passengers
- Denver (DEN) – 953,000 passengers.
9
San Francisco (SFO) – Burbank (BUR)
175 flights
Hollywood-Burbank Airport (BUR) is the ninth-busiest domestic destination served by United Airlines from San Francisco International Airport (SFO). In January 2025, the carrier will operate 175 flights in each direction, equating to up to six flights per day. United Airlines deploys a mix of mainline Airbus A319s, Boeing 737-800s, and Boeing 737 MAX 8s on the route, as well as SkyWest Airlines’ Embraer E175 aircraft on behalf of the regional subsidiary United Express.
Photo: Vicenzo Pace | Simple Flying
Last year, San Francisco was the fifth-busiest destination from Hollywood-Burbank Airport, with more than 232,000 passengers annually. This put the route ahead of Denver (DEN) with 221,000 passengers and behind Sacramento (SMF) with 258,000 passengers each year.
8
San Francisco (SFO) – San Diego (SAN)
184 flights
In January 2025, United Airlines will operate a total of 184 in each direction between San Francisco International Airport (SFO) and San Diego International Airport (SAN). The carrier deploys a mix of Boeing 737-800s and 737 MAX 9s on the busy route, with a scheduled block time of around one hour and 40 minutes each way.
Photo: Lukas Souza | Simple Flying
On its services between San Francisco and San Diego, United Airlines faces direct competition from the following carriers:
- Alaska Airlines
- Frontier Airlines
- Southwest Airlines.
7
San Francisco (SFO) – Washington (IAD)
187 flights
United Airlines’ seventh-busiest domestic route from San Francisco International Airport (SFO) is to Washington Dulles International Airport (IAD), with the carrier operating a total of 187 flights in each direction in January 2025.
Photo: Vincenzo Pace | Simple Flying
United Airlines goes head-to-head with Alaska Airlines, and deploys a mix of narrowbody and widebody aircraft on the 2,419-mile route, including:
- Boeing 737-800
- Boeing 737 MAX 9
- Boeing 757-200
- Boeing 787-8
- Boeing 777-200.
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6
San Francisco (SFO) – Las Vegas (LAS)
201 flights
The popular business and leisure route to and from Las Vegas Harry Reid International Airport (LAS) is United Airlines’ sixth-busiest domestic route from San Francisco International Airport (SFO). In January 2025, the Star Alliance carrier will operate a total of 201 flights in each direction on the route.
Photo: San Francisco International Airport, Ryan Patterson
United Airlines faces direct competition from Alaska Airlines, Frontier Airlines, and Southwest Airlines. Last year, Las Vegas was the sixth-busiest domestic destination from San Francisco International Airport, with more than 788,000 passengers across all carriers, behind the following five routes:
- Los Angeles (LAX) – 1,339,000 passengers
- Chicago (ORD) – 922,000 passengers
- New York (JFK) – 917,000 passengers
- Denver (DEN) – 872,000 passengers
- Newark (EWR) – 791,000 passengers.
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5
San Francisco (SFO) – Houston (IAH)
238 flights
In January 2025, United Airlines will operate a total of 238 flights in each direction between San Francisco International Airport (SFO) and Houston George Bush Intercontinental Airport (IAH). With both airports serving as major hubs for the carrier, it is no surprise to see so many flights operated by United Airlines between the two.
Photo: Vincenzo Pace | Simple Flying
United Airlines is the only carrier to operate the 1,635-mile-long route, which is the fourth-longest route to feature on this list. The carrier deploys a mix of Boeing 737-800s, 737 MAX 9s, 757-200s, and 777-200s between the two cities.
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4
San Francisco (SFO) – Chicago (ORD)
254 flights
United Airlines’ fourth-busiest domestic destination from San Francisco International Airport (SFO) is Chicago O’Hare International Airport (ORD). In January 2025, the carrier will operate a total of 254 flights in each direction between the two airports, equating to up to eight flights per day.
Photo: Markus Mainka | Shutterstock
United Airlines goes head-to-head with Alaska Airlines and American Airlines on this route, and Southwest Airlines also serves Chicago Midway Airport (MDW) from San Francisco. With more than 922,000 passengers across all airlines, Chicago O’Hare International Airport was the second-busiest domestic route from San Francisco International Airport.
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3
San Francisco (SFO) – Los Angeles (LAX)
281 flights
In January 2025, United Airlines will operate a total of 281 flights in each direction between San Francisco International Airport (SFO) and Los Angeles International Airport (LAX), deploying a mix of Airbus A320s, Boeing 737-800s, and Boeing 737 MAX 9s on the 337-mile-long route. United Airlines operates a large fleet of Boeing 737s, made up of the following variants:
- Boeing 737-700 x 40
- Boeing 737-800 x 141
- Boeing 737 MAX 8 x 111
- Boeing 737-900 x 12
- Boeing 737-900ER x 136
- Boeing 737 MAX 9 x 86.
Photo: HMBSoFL Photography | Shutterstock
The carrier also has an order for 167 Boeing 737 MAX 10s and will become the launch customer for the aircraft when it is eventually delivered. Los Angeles is the busiest domestic destination from San Francisco, with more than one million passengers across all carriers. United Airlines faces direct competition from the following carriers:
- Alaska Airlines
- American Airlines
- Delta Air Lines
- Frontier Airlines
- Southwest Airlines.
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2
San Francisco (SFO) – Newark (EWR)
285 flights
United Airlines’ second-busiest domestic route from San Francisco International Airport (SFO) is its transcontinental route to Newark Liberty International Airport (EWR). In January 2025, the carrier will operate a total of 285 flights in each direction between the two airports.
Photo: EQRoy | Shutterstock
Newark Liberty International Airport serves as United Airlines’ primary transatlantic hub, with the Star Alliance carrier operating an ever-growing number of services to destinations across Europe, the Middle East, and Africa. Among United Airlines’ newest European destinations to be served from Newark in 2025 are Bilbao (BIO), Funchal (FNC), Palermo (PMO), and Faro (FAO).
1
San Francisco (SFO) – Denver (DEN)
302 flights
In January 2025, United Airlines will operate 302 flights each way between San Francisco International Airport (SFO) and Denver International Airport (DEN), making it the carrier’s busiest domestic route from San Francisco by number of flights.
Photo: Vincenzo Pace | Simple Flying
Denver International Airport is also a major hub for United Airlines, and is connected to San Francisco with up to ten daily services operated by a mix of Boeing 737 and 757 family aircraft. The carrier goes head-to-head with both Frontier Airlines and Southwest Airlines on the route, although neither can compete with United Airlines in terms of flight frequency.
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United Airlines’ ten busiest domestic routes from San Francisco International Airport in January 2025 are summarized in the table below:
Destination |
Number of flights (one way) |
---|---|
Seattle (SEA) |
160 |
Burbank (BUR) |
175 |
San Diego (SAN) |
184 |
Washington (IAD) |
187 |
Las Vegas (LAS) |
201 |
Houston (IAH) |
238 |
Chicago (ORD) |
254 |
Los Angeles (LAX) |
281 |
Newark (EWR) |
285 |
Denver (DEN) |
302 |