Cheap flights from St. Louis to London from £255

The cheapest month to fly to London from St. Louis is in March. Flight prices, which tend to average around £601, are often lower during this time because this is during the off-season. The month of April is another great option to travel to London, with average flight prices from St. Louis averaging around £614.

Our data shows that Wednesday is the least expensive day to fly to London. Tickets to fly out on this day can be as low as £768. When flying out on a Tuesday, the most expensive travel day of the week, you can expect to see flight prices from St. Louis to London for around £914.

Fly from Lambert-St Louis to London Heathrow for the best Lambert-St Louis - London flight prices

You are more likely to see cheaper flights to London from St. Louis when booking weeks ahead of your departure date. In general, you can expect to find flights to London for around £777 when searching weeks before you fly. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to London from St. Louis for as low as £677 on momondo.

There are 2 cabin classes available to choose from on St. Louis 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 52% on your flight if you consider stops on a St. Louis to London flight.

Historically, on average around 18% of flights between St. Louis and London have experienced a delay on any given week. The average delay length over the past 12 months has been 114 minutes.

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

Monday 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, British Airways have had the fewest delays on this route over the last 12 months, with about 18% of their flights experiencing any sort of delay.

The number of flights available between St. Louis and London is 2 per day as of October 2026. The most frequent departure time is 21:00, with 100% of daily flights leaving in the evening.

The number of flights available between St. Louis and London is 15 per week as of October 2026. The most frequent departure day is Tue, with 33% of weekly flights leaving on this day.