United Airlines plans two winter San Francisco-Barcelona round trips

United Airlines plans to add two winter round trips between San Francisco and Barcelona using Boeing 777-300ER aircraft, a limited addition aimed at Mobile World Congress traffic rather than a full winter extension of the route. According to Simple Flying, citing schedule information reported by Aeroroutes, the flights will operate in February and March 2027.

The distinction matters for anyone building a trip around the news. United already serves San Francisco International Airport and Barcelona El Prat Airport regularly during the summer, Simple Flying reported. This addition puts the route into the upcoming IATA winter schedule for two specific rotations; it does not establish recurring winter service.

The reporting describes a schedule addition. For travelers, the useful details are the narrow operating window, the conference timing and the larger aircraft assigned to the flights.

San Francisco-Barcelona Winter Flight Schedule

According to Simple Flying, outbound flight UA672 will leave San Francisco at 7 p.m. local time on February 27 and March 3, arriving in Barcelona at 3:20 p.m. the following day. Return flight UA673 will depart Barcelona at 5:30 p.m. on February 28 and March 4, reaching San Francisco at 8:50 p.m. the same day.

Those dates create two distinct aircraft rotations:

• First rotation: UA672 departs San Francisco on February 27 and arrives in Barcelona on February 28. UA673 returns from Barcelona on February 28.
• Second rotation: UA672 departs San Francisco on March 3 and arrives in Barcelona on March 4. UA673 returns from Barcelona on March 4.

Simple Flying ties the flights to Mobile World Congress, scheduled in Barcelona from March 1 to 4, 2027.

For a San Francisco-origin conference trip, the relevant combination is the February 27 outbound and March 4 return, not either aircraft rotation taken as an individual passenger itinerary. The first outbound arrives before the conference begins; the second return leaves on its final day. That distinction is easy to miss in a report framed around two round trips.

The March 3 departure from San Francisco has a different limitation: Its next-day arrival falls on March 4, the conference’s final date. It is not an alternative outbound for someone intending to attend the event from the start. Likewise, the February 28 Barcelona departure precedes the conference.

Why United Is Adding These Particular Flights

Simple Flying identifies short-term corporate demand around Mobile World Congress as the reason for the additional service. The publication described the trade show’s latest edition as marking its 20th anniversary in Barcelona and attracting almost 105,000 attendees.

That is the context for this addition. United is not introducing Barcelona as a new destination from San Francisco, nor does the reported schedule indicate an uninterrupted winter operation. It is placing two round trips around a major telecommunications trade show on an otherwise seasonal route.

For conference travelers, the direct service is useful only if those dates match the trip. A 5:30 p.m. departure on March 4 also deserves attention when planning the final conference day. The published schedule establishes the flight time, not whether it accommodates a particular attendee’s closing meetings.

What the Boeing 777-300ER Adds

United plans to use its 350-seat Boeing 777-300ER for both rotations, according to Simple Flying’s account of the carrier’s seat maps. The configuration includes 60 Polaris business-class seats, 24 Premium Plus premium-economy seats and 266 economy seats.

Within that economy total, 62 seats are designated Economy Plus. Simple Flying lists their seat pitch at 34 inches, compared with 31 inches for the other economy seats. Economy Plus is therefore part of the economy inventory, not an additional cabin to count on top of the 266 seats.

That distinction also matters when choosing a seat. Premium Plus and Economy Plus are different products in the reported layout: The former is the premium-economy cabin; the latter consists of extra-legroom seats within economy. Fares and ticket conditions for these special flights are not detailed in Simple Flying’s report, so the aircraft assignment alone does not establish the cost or inclusions of a booking.

A Larger Aircraft Than the Route’s Recent Equipment

The winter assignment also differs from the route’s recent aircraft history. Citing Cirium, Simple Flying reported that United first served San Francisco-Barcelona in 2024, operating 156 flights from May to October with the 276-seat Boeing 777-200ER. In 2025, the publication recorded 179 rotations from March to October using that aircraft type.

For 2026, Simple Flying reported 159 scheduled rotations and a switch to the Boeing 787-9 in September. The 787-9 configuration described in the report carries 257 passengers, including 48 in Polaris, 21 in Premium Plus and 188 in economy.

The planned 777-300ER therefore brings more seats in each of those categories than the 787-9 configuration cited for the route. But aircraft size should not be confused with schedule breadth. This remains a tightly targeted addition: two winter rotations, with the clearest conference itinerary pairing the first San Francisco departure with the last Barcelona return.