Cheap flights from San Francisco to London from $377

The cheapest month to fly to London from San Francisco is in February. Flight prices, which tend to average around $644, are often lower during this time because this is during the off-season. The month of January is another great option to travel to London, with average flight prices from San Francisco averaging around $645.

The cheapest day to depart from San Francisco to London is on a Wednesday. Travelers who choose to depart for London on a Wednesday will often find tickets for as low as $806. If your travel schedule is flexible, try to avoid departing on a Saturday because tickets tend to average around $939. These prices are subject to change though, so be sure to set up a Price Alert for flights to London.

Flying to London from San Francisco in the afternoon is the least expensive time of day to depart. momondo users have found prices as low as $855 when looking at flights departing in the afternoon. Flights to London are more costly at noon, with an average ticket price of $941. Departure times at noon fall within the peak daily travel times, which is why tickets can be more expensive.

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

You are more likely to see cheaper flights to London from San Francisco when booking weeks ahead of your departure date. In general, you can expect to find flights to London for around $764 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to London from San Francisco for as low as $734 on momondo.

There are 4 cabin classes available to choose from on San Francisco to London flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

You could potentially save up to 23% on your flight if you consider stops on a San Francisco to London flight.

As of March 2026, prices for San Francisco to London flights are approximately 29% more expensive when compared to flights at the same time last year.

United Airlines, KLM, and Delta are the most popular carriers operating from San Francisco to London

United Airlines, British Airways and Virgin Atlantic are the top three most popular airlines that fly to London from San Francisco according to our data. United Airlines is the first choice among our users, with 44% of people opting to fly with this airline when traveling to London. Keep in mind that there are 20 different airlines that fly to London on a routine basis, so you have a few additional options to choose from.

Historically, on average around 11% of flights between San Francisco and London have experienced a delay on any given week. The average delay length over the past 12 months has been 149 minutes.

Generally, flights departing at night tend to experience fewer delays. Flights in the early afternoon have, in the past, seen delays more frequently in comparison.

Monday is statistically the day of the week which experiences the fewest number of delays on this flight route. Thursday has historically seen more delays on average compared to the rest of the week.

According to our data, British Airways have had the least number of delays on this route over the last 12 months; with about 9% of their flights experiencing any sort of delay.

Lisbon (LIS) was the most common stop: 21% of momondo users choosing 1-stop flights on this route connected there.

Flights via New York (JFK) offer the lowest average round-trip price of $516.

Flights connecting via Phoenix (PHX) have the shortest average one-way travel time: 13h 27m.

New York (JFK) has the shortest average layover time for this route: 1h 26m.

31 flights are operational daily from San Francisco to London as of March 2026. The most popular departure time for this route is 6:00PM, with 60% of flights per day taking off in the evening.

As of March 2026, 217 flights take off from San Francisco and land in London each week. The most common flight departure day for this route is Mon, with 14% of weekly flights taking off on this day.