Cheap flights from Chicago to London from $378

The month of January is, on average, the cheapest month to fly to London Heathrow Airport from Chicago, with most prices found around $619. If you’re not able to fly to London Heathrow Airport in January, then February is your next best option. Flight prices from Chicago to London Heathrow Airport during February average around $638.

Our data shows that Tuesday is the least expensive day to fly to London Heathrow Airport. Tickets to fly out on this day can be as low as $759. The most expensive day to fly to London Heathrow Airport is Saturday, with ticket prices averaging around $944.

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 $819. Keep in mind that these prices may fluctuate based on what airline you choose and the time of year you plan to travel. Flights in the afternoon are often more expensive with an average ticket price of $839.

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 $786 when searching weeks out. 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 $712 on momondo.

There are 4 cabin classes available to choose from on Chicago to London Heathrow 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 8% on your flight if you consider stops on a Chicago to London Heathrow Airport flight.

As of March 2026, prices for Chicago to London Heathrow Airport flights are approximately 45% more expensive when compared to flights at the same time last year.

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

British Airways, Iberia and American 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 50% of people opting to fly with this airline when traveling to London Heathrow Airport. Keep in mind that there are 16 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 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 169 minutes.

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

Tuesday is statistically the day of the week which experiences the fewest number of 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 least number of delays on this route over the last 12 months; with about 25% of their flights experiencing any sort of delay.

Reykjavik (KEF) was the most common stop: 43% of momondo users choosing 1-stop flights on this route connected there.

Flights via Copenhagen (CPH) offer the lowest average round-trip price of $586.

Flights connecting via Dublin (DUB) have the shortest average one-way travel time: 10h 09m.

Reykjavik (KEF) has the shortest average layover time for this route: 1h 20m.

As of March 2026, there are 44 flights per day flying from Chicago to London Heathrow Airport. The most common time of day flights depart is 6:00PM, with 86% of flights taking off in the evening.

As of March 2026, there are 310 flights per week flying from Chicago to London Heathrow Airport. The most common day of the week flights depart is Mon, with 15% of flights taking off on this day.