Cheap flights from St. Louis to London from £194

The cheapest month to fly to London from St. Louis is in April. Flight prices, which tend to average around £87, are often lower during this time because this is during the off-season. The month of March is another great option to travel to London, with average flight prices from St. Louis averaging around £359.

Our data shows that Friday is the least expensive day to fly to London. Tickets to fly out on this day can be as low as £474. 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 £900.

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 £647 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 £525 on momondo.

There is only 1 cabin class 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.

As of June 2026, prices for St. Louis to London flights are approximately 25% more expensive when compared to flights at the same time last year.

Historically, on average around 27% 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 162 minutes.

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

Wednesday 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, British Airways have had the fewest delays on this route over the last 12 months, with about 27% of their flights experiencing any sort of delay.

Atlanta (ATL) was the most common stop: 86% of momondo users choosing one-stop flights on this route connected there.

Flights via Dallas (DFW) offer the lowest average return price of £524.

Flights connecting via Atlanta (ATL) have the shortest average one-way travel time: 10h 28m.

Atlanta (ATL) has the shortest average stopover time for this route: 1h 31m.

The number of flights available between St. Louis and London is 2 per day as of June 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 June 2026. The most frequent departure day is Tue, with 33% of weekly flights leaving on this day.