Cheap flights from Chicago to the United Kingdom from £125

The cheapest month to fly to United Kingdom from Chicago is in September. Flight prices, which tend to average around £489, are often lower during this time because this is during the off-season. If you are unable to visit United Kingdom during the month of September, then departing from Chicago during the month October is also very affordable. Most momondo users find prices during this month for around £489.

The cheapest day to depart from Chicago to United Kingdom is on a Sunday. Travellers who choose to depart for United Kingdom on a Sunday will often find tickets for as low as £506. When flying out on a Friday, the most expensive travel day of the week, you can expect to see flight prices from Chicago to United Kingdom for around £672.

The cheapest time of day to fly to United Kingdom is in the evening when flights can be purchased for as low as £570. Try not to purchase tickets in the afternoon because they tend to be around £611. Of course, these prices can vary depending on the time of year and what airport you fly to.

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

You are more likely to see cheaper flights to United Kingdom from Chicago when booking weeks ahead of your departure date. In general, you can expect to find flights to United Kingdom for around £585 when searching weeks before you fly. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to United Kingdom from Chicago for as low as £518 on momondo.

There are 4 cabin classes available to choose from on Chicago to United Kingdom flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

TAP AIR PORTUGAL, Delta, and United Airlines are the most popular carriers operating from Chicago to United Kingdom

British Airways, Aer Lingus and Iberia are the top three most popular airlines that fly to United Kingdom from Chicago according to our data. British Airways is the first choice among our users, with 56% of people opting to fly with this airline when travelling to United Kingdom. Keep in mind that there are 8 different airlines that fly to United Kingdom on a routine basis, so you have a few additional options to choose from.

Historically, on average around 26% of flights between Chicago and United Kingdom have experienced a delay on any given week. The average delay length over the past 12 months has been 172 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.

38 flights are operational daily from Chicago to United Kingdom as of March 2026. The most popular departure time for this route is 17:00, with 60% of flights per day taking off in the evening.

The number of flights available between Chicago and United Kingdom is 270 per week as of March 2026. The most frequent departure day is Mon, with 17% of weekly flights leaving on this day.