Cheap flights from Chicago to London from 621 $

You can save on your Chicago-London plane ticket and get the cheapest flight if you avoid peak season, book in advance and are flexible about dates and times for both your outbound and return flight.

To find out which day is the cheapest to fly, just start a search in our cheap flight finder. Tell us where you are flying from, where you want to go and what dates you're thinking of. We'll show you the cheapest flights not only for the date you searched but on surrounding days as well, for both the outbound and return flight, so you can find the best deal. And be sure to look carefully at the different flight options we offer every day: certain times may save you even more on the price of your ticket.

You can get the cheapest flights by travelling outside peak season. Although it depends on the destination, in general Christmas, Easter and school holidays are peak season. Besides, if you're thinking about a weekend getaway, the earlier you book your flight, the better the price.

You can find cheap flights any day of the week. The key to finding the best deals is to book early and be flexible. Usually, the earlier you book your plane tickets, the cheaper they will be. Besides, if you have some wiggle room as regards dates and times of flights, you'll be able to choose the cheapest price.

The earlier you book your flights, the better the prices. Prices depend on the remaining seats on the flight and whether the cheapest fares (Economy) are still available or are selling out. So booking in advance is essential to get cheap flights.

Iberia offers different fares to guarantee the best deal for your travel needs. The Basic fare guarantees you the cheapest flight.