Cheap flights from Chicago to London from £242

The cheapest month to fly to London from Chicago is in January. Flight prices, which tend to average around £485, are often lower during this time because this is during the off-season. The month of February is another great option to travel to London, with average flight prices from Chicago averaging around £526.

Our data shows that Monday is the least expensive day to fly to London. Tickets to fly out on this day can be as low as £673. When flying out on a Saturday, the most expensive travel day of the week, you can expect to see flight prices from Chicago to London for around £1,038.

The cheapest time of day to fly to London is in the evening when flights can be purchased for as low as £837. Flights in the afternoon are often more expensive, with an average ticket price of £896.

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 £691 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 £639 on momondo.

There are 3 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 5% on your flight if you consider stops on a Chicago to London flight.

As of October 2026, prices for Chicago to London flights are approximately 42% more expensive when compared to flights at the same time last year.

United Airlines, Delta, and Icelandair are the most popular carriers operating from Chicago to London

British Airways, Aer Lingus and United Airlines 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 36% 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 23% 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 161 minutes.

Generally, flights departing in the early afternoon tend to experience fewer delays. Flights departing at night 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 22% of their flights experiencing any sort of delay.

Dublin (DUB) was the most common stop: 57% of momondo users choosing one-stop flights on this route connected there.

Flights via Reykjavik (KEF) offer the lowest average return price of £445.

Flights connecting via Reykjavik (KEF) have the shortest average one-way travel time: 10h 20m.

Reykjavik (KEF) has the shortest average stopover time for this route: 0h 55m.

As of October 2026, there are 38 flights per day flying from Chicago to London. The most common time of day flights depart is 21:00, with 66% of flights taking off in the evening.

The number of flights available between Chicago and London is 272 per week as of October 2026. The most frequent departure day is Wed, with 21% of weekly flights leaving on this day.