Cheap flights from Boston to San Francisco from £109

The month of September is, on average, the cheapest month to fly to San Francisco from Boston, with most prices found around £253. If you are unable to visit San Francisco during the month of September, then departing from Boston during the month January is also very affordable. Most momondo users find prices during this month for around £253.

The cheapest day to depart on your flight to San Francisco is on a Friday when prices can be found for as low as £230. This is often the case because there is less demand to fly during this day of the week. Flights from Boston to San Francisco on a Saturday will generally be more expensive and average around £1,684. 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 evening. Flights from Boston to San Francisco during this time can be as low as £343. Try not to purchase tickets at midday because they tend to be around £720. Of course, these prices can vary depending on the time of year and what airport you fly to.

Fly from Boston Logan Intl to San Francisco for the best Boston Logan Intl - San Francisco flight prices

You are more likely to see cheaper flights to San Francisco from Boston when booking weeks ahead of your departure date. In general, you can expect to find flights to San Francisco for around £283 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 Boston for as low as £200 on momondo.

There are 3 cabin classes available to choose from on Boston Logan Intl to San Francisco flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Historically, on average around 16% of flights between Boston and San Francisco have experienced a delay on any given week. The average delay length over the past 12 months has been 176 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. Sunday 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 14% of their flights experiencing any sort of delay.

As of March 2026, 28 flights take off from Boston and land in San Francisco each day. The most common flight departure time for this route is 07:00, with 36% of daily flights taking off at midday.

200 flights are operational weekly from Boston to San Francisco as of March 2026. The most popular departure day for this route is Sun, with 19% of flights per week taking off on this day.