Cheap flights from Chicago to London from £254

The cheapest month to fly to London from Chicago is in September. Flight prices, which tend to average around £484, are often lower during this time because this is during the off-season. The month of October is another great option to travel to London, with average flight prices from Chicago averaging around £485.

Our data shows that Sunday is the least expensive day to fly to London. Tickets to fly out on this day can be as low as £501. When flying out on a Friday, the most expensive travel day of the week, you can expect to see flight prices from Chicago to London for around £666.

The cheapest time of day to fly to London is in the evening when flights can be purchased for as low as £565. Flights in the afternoon are often more expensive, with an average ticket price of £605.

Fly from Chicago O'Hare Intl to London Heathrow for the best Chicago - London flight prices

You are more likely to see cheaper flights to London from Chicago when booking weeks ahead of your departure date. In general, you can expect to find flights to London for around £578 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 Chicago for as low as £513 on momondo.

There are 4 cabin classes available to choose from on Chicago 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 Chicago to London flight.

As of February 2026, prices for Chicago to London flights are approximately 30% more expensive when compared to flights at the same time last year.

JetBlue, British Airways, and United Airlines are the most popular carriers operating from Chicago to London

British Airways, Iberia and Aer Lingus are the top three most popular airlines that fly to London from Chicago according to our data. British Airways is the first choice among our users, with 58% of people opting to fly with this airline when travelling to London. Keep in mind that there are 7 different airlines that fly to London on a routine basis, so you have a few additional options to choose from.

Historically, on average around 26% of flights between Chicago and London have experienced a delay on any given week. The average delay length over the past 12 months has been 170 minutes.

Generally, flights departing in the early afternoon tend to experience fewer delays. Flights departing in the morning 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, American Airlines have had the fewest delays on this route over the last 12 months, with about 25% of their flights experiencing any sort of delay.

As of February 2026, there are 45 flights per day flying from Chicago to London. The most common time of day flights depart is 21:00, with 61% of flights taking off in the evening.

The number of flights available between Chicago and London is 315 per week as of February 2026. The most frequent departure day is Mon, with 14% of weekly flights leaving on this day.