Cheap flights from Chicago to London from £227

In general, January is the cheapest month to fly from Chicago to London Heathrow Airport. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around £476. The month of October is another great option to travel to London Heathrow Airport, with average flight prices from Chicago averaging around £521.

On average, the least expensive day to fly to London Heathrow Airport from Chicago is on a Monday. momondo users have found tickets for Monday departures for as low as £551. However, this price may fluctuate depending on the airline, the season, and holidays. Be sure to avoid booking your departure on a Saturday as prices are generally higher than usual. According to our data, the average ticket price to London Heathrow Airport on Saturday is £902.

According to our data, the cheapest time of day to fly to London Heathrow Airport is in the evening. momondo users have found flights departing from Chicago to London Heathrow Airport in the evening for as low as £701. Keep in mind that these prices may fluctuate based on what airline you choose and the time of year you plan to travel. If you have a flexible travel schedule, then try to avoid flying in the afternoon when prices are £789 on average. Flights to London Heathrow Airport from Chicago in the afternoon are generally more expensive because this time of day is more convenient for travellers’ schedules.

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

You are more likely to see cheaper flights to London Heathrow Airport from Chicago when booking weeks ahead of your departure date. In general, you can expect to find flights to London Heathrow Airport for around £645 when searching weeks before you fly. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to London Heathrow Airport from Chicago for as low as £600 on momondo.

There are 3 cabin classes available to choose from on Chicago to London Heathrow Airport 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 4% on your flight if you consider stops on a Chicago to London Heathrow Airport flight.

As of August 2026, prices for Chicago to London Heathrow Airport flights are approximately 16% cheaper when compared to flights at the same time last year.

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

British Airways, Aer Lingus and United Airlines are the top three most popular airlines that fly to London Heathrow Airport from Chicago according to our data. British Airways is the first choice among our users, with 40% of people opting to fly with this airline when travelling to London Heathrow Airport. Keep in mind that there are 7 different airlines that fly to London Heathrow Airport on a routine basis, so you have a few additional options to choose from.

Historically, on average around 25% 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 174 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, British Airways have had the fewest delays on this route over the last 12 months, with about 23% of their flights experiencing any sort of delay.

Dublin (DUB) was the most common stop: 50% of momondo users choosing one-stop flights on this route connected there.

Flights via Dublin (DUB) offer the lowest average return price of £668.

Flights connecting via Dublin (DUB) have the shortest average one-way travel time: 10h 32m.

Dublin (DUB) has the shortest average stopover time for this route: 1h 41m.

As of August 2026, there are 48 flights per day flying from Chicago to London Heathrow Airport. The most common time of day flights depart is 21:00, with 78% of flights taking off in the evening.

The number of flights available between Chicago and London Heathrow Airport is 338 per week as of August 2026. The most frequent departure day is Thu, with 17% of weekly flights leaving on this day.