Cheap flights from London to San Francisco from £422

The month of February is, on average, the cheapest month to fly to San Francisco from London, with most prices found around £390. If you are unable to visit San Francisco during the month of February, then departing from London during the month November is also very affordable. Most momondo users find prices during this month for around £411.

The cheapest day to depart on your flight to San Francisco is on a Thursday when prices can be found for as low as £567. This is often the case because there is less demand to fly during this day of the week. Flights from London to San Francisco on a Sunday will generally be more expensive and average around £654. Keep in mind that these prices on both days could fluctuate depending on the season and the demand.

Our most recent data shows that the best time of day to fly to San Francisco is in the morning. Flights from London to San Francisco during this time can be as low as £565. Try not to purchase tickets at midday because they tend to be around £783. Of course, these prices can vary depending on the time of year and what airport you fly to.

Fly from London Heathrow to San Francisco for the best London - San Francisco flight prices

You are more likely to see cheaper flights to San Francisco from London when booking weeks ahead of your departure date. In general, you can expect to find flights to San Francisco for around £512 when searching weeks before you fly. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to San Francisco from London for as low as £453 on momondo.

You could potentially save up to 14% on your flight if you consider stops on a London to San Francisco flight.

As of May 2026, prices for London to San Francisco flights are approximately 33% more expensive when compared to flights at the same time last year.

SWISS, JetBlue, and Lufthansa are the most popular carriers operating from London to San Francisco

Virgin Atlantic, British Airways and Lufthansa are the top three most popular airlines that fly to San Francisco from London according to our data. Virgin Atlantic is the first choice among our users, with 41% of people opting to fly with this airline when travelling to San Francisco. Keep in mind that there are 18 different airlines that fly to San Francisco on a routine basis, so you have a few additional options to choose from.

Historically, on average around 12% of flights between London and San Francisco have experienced a delay on any given week. The average delay length over the past 12 months has been 144 minutes.

Generally, flights departing in the morning tend to experience fewer delays. Flights departing in the evening have, in the past, seen delays more frequently in comparison.

Tuesday is statistically the day of the week that experiences the fewest delays on this flight route. Wednesday has historically seen more delays on average compared to the rest of the week.

According to our data, United Airlines have had the fewest delays on this route over the last 12 months, with about 11% of their flights experiencing any sort of delay.

Dublin (DUB) was the most common stop: 38% of momondo users choosing one-stop flights on this route connected there.

Flights via Frankfurt am Main (FRA) offer the lowest average return price of £361.

Flights connecting via Denver (DEN) have the shortest average one-way travel time: 13h 54m.

Los Angeles (LAX) has the shortest average stopover time for this route: 1h 16m.

The number of flights available between London and San Francisco is 41 per day as of May 2026. The most frequent departure time is 10:00, with 56% of daily flights leaving in the afternoon.

The number of flights available between London and San Francisco is 288 per week as of May 2026. The most frequent departure day is Mon, with 15% of weekly flights leaving on this day.