Cheap flights from Illinois to Key West from $136

In general, February is the cheapest month to fly from Illinois to Key West. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $104. If you are unable to visit Key West during the month of February, then departing from Illinois during the month October is also very affordable. Most momondo users find prices during this month for around $162.

On average, the least expensive day to fly to Key West from Illinois is on a Tuesday. momondo users have found tickets for Tuesday departures for as low as $354. However, this price may fluctuate depending on the airline, the season, and holidays. When flying out on a Sunday, the most expensive travel day of the week, you can expect to see flight prices from Illinois to Key West for around $507.

According to our data, the cheapest time of day to fly to Key West is in the afternoon. momondo users have found flights departing from Illinois to Key West in the afternoon for as low as $449. Keep in mind that these prices may fluctuate based on what airline you choose and the time of year you plan to travel. Flights to Key West are more costly in the morning, with an average ticket price of $461. Departure times in the morning fall within the peak daily travel times, which is why tickets can be more expensive.

Fly from Chicago O'Hare Intl to Key West for the best Illinois - Key West flight prices

You are more likely to see cheaper flights to Key West from Illinois when booking weeks ahead of your departure date. In general, you can expect to find flights to Key West for around $430 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Key West from Illinois for as low as $369 on momondo.

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

Allegiant Air, United Airlines, and Delta are the most popular carriers operating from Illinois to Key West

American Airlines, United Airlines and Delta are the top three most popular airlines that fly to Key West from Illinois according to our data. American Airlines is the first choice among our users, with 60% of people opting to fly with this airline when traveling to Key West. Keep in mind that there are 3 different airlines that fly to Key West on a routine basis, so you have a few additional options to choose from.

The number of flights available between Illinois and Key West is 2 per day as of June 2026. The most frequent departure time is 10:00AM, with 100% of daily flights leaving at noon.

As of June 2026, there are 18 flights per week flying from Illinois to Key West. The most common day of the week flights depart is Mon, with 17% of flights taking off on this day.