Cheap flights from Illinois to the United Kingdom from £189

The cheapest month to fly to United Kingdom from Illinois is in January. Flight prices, which tend to average around £476, 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 January, then departing from Illinois during the month February is also very affordable. Most momondo users find prices during this month for around £516.

The cheapest day to depart from Illinois to United Kingdom is on a Monday. Travellers who choose to depart for United Kingdom on a Monday will often find tickets for as low as £697. When flying out on a Saturday, the most expensive travel day of the week, you can expect to see flight prices from Illinois to United Kingdom for around £1,029.

The cheapest time of day to fly to United Kingdom is in the evening when flights can be purchased for as low as £840. Try not to purchase tickets in the afternoon because they tend to be around £897. 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 Illinois - United Kingdom flight prices

You are more likely to see cheaper flights to United Kingdom from Illinois when booking weeks ahead of your departure date. In general, you can expect to find flights to United Kingdom for around £695 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 Illinois for as low as £647 on momondo.

There are 3 cabin classes available to choose from on Illinois to United Kingdom flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Icelandair, British Airways, and United Airlines are the most popular carriers operating from Illinois to United Kingdom

Aer Lingus, British Airways and Icelandair are the top three most popular airlines that fly to United Kingdom from Illinois according to our data. Aer Lingus is the first choice among our users, with 41% of people opting to fly with this airline when travelling to United Kingdom. Keep in mind that there are 7 different airlines that fly to United Kingdom on a routine basis, so you have a few additional options to choose from.

As of October 2026, there are 35 flights per day flying from Illinois to United Kingdom. The most common time of day flights depart is 22:00, with 81% of flights taking off in the evening.

The number of flights available between Illinois and United Kingdom is 247 per week as of October 2026. The most frequent departure day is Mon, with 17% of weekly flights leaving on this day.