Cheap flights from Illinois to London from $312

The cheapest month to fly to London from Illinois is in November. Flight prices, which tend to average around $639, are often lower during this time because this is during the off-season. The month of April is another great option to travel to London, with average flight prices from Illinois averaging around $675.

The cheapest day to depart from Illinois to London is on a Tuesday. Travelers who choose to depart for London on a Tuesday will often find tickets for as low as $786. If your travel schedule is flexible, try to avoid departing on a Saturday because tickets tend to average around $985. These prices are subject to change though, so be sure to set up a Price Alert for flights to London.

Flying to London from Illinois in the evening is the least expensive time of day to depart. momondo users have found prices as low as $849 when looking at flights departing in the evening. Flights to London are more costly in the afternoon, with an average ticket price of $867. Departure times in the afternoon fall within the peak daily travel times, which is why tickets can be more expensive.

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

You are more likely to see cheaper flights to London from Illinois when booking weeks ahead of your departure date. In general, you can expect to find flights to London for around $798 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to London from Illinois for as low as $710 on momondo.

Delta, Virgin Atlantic, and KLM are the most popular carriers operating from Illinois to London

British Airways, American Airlines and United Airlines are the top three most popular airlines that fly to London from Illinois according to our data. British Airways is the first choice among our users, with 51% of people opting to fly with this airline when traveling to London. Keep in mind that there are 18 different airlines that fly to London on a routine basis, so you have a few additional options to choose from.

As of April 2026, there are 50 flights per day flying from Illinois to London. The most common time of day flights depart is 5:00PM, with 64% of flights taking off in the evening.

355 flights are operational weekly from Illinois to London as of April 2026. The most popular departure day for this route is Wed, with 17% of flights per week taking off on this day.