Cheap flights from San Diego to Illinois from $121

The cheapest month to fly to Illinois from San Diego is in February. Flight prices, which tend to average around $260, are often lower during this time because this is during the off-season. If you aren’t able to travel to Illinois during the month of February, then flying in January is also cheap. Prices for this month can be found on momondo for an average of $265.

The cheapest day to depart from San Diego to Illinois is on a Wednesday when prices can be found for as low as $410. Flights from San Diego to Illinois on a Sunday will generally be more expensive and average around $577. Keep in mind that these prices on both days could fluctuate depending on the season and the demand.

Our most recent data shows that the best time of day to fly to Illinois is in the afternoon. Flights from San Diego to Illinois during this time can be as low as $364. Flights at noon are often more expensive with an average ticket price of $481.

Fly from San Diego to Chicago Midway for the best San Diego - Illinois flight prices

You are more likely to see cheaper flights to Illinois from San Diego when booking weeks ahead of your departure date. In general, you can expect to find flights to Illinois for around $325 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Illinois from San Diego for as low as $273 on momondo.

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

Frontier, Alaska Airlines, and United Airlines are the most popular carriers operating from San Diego to Illinois

American Airlines, United Airlines and Alaska Airlines are the top three most popular airlines that fly to Illinois from San Diego according to our data. American Airlines is the first choice among our users, with 42% of people opting to fly with this airline when traveling to Illinois. Keep in mind that there are 7 different airlines that fly to Illinois on a routine basis, so you have a few additional options to choose from.

As of October 2026, 47 flights take off from San Diego and land in Illinois each day. The most common flight departure time for this route is 10:00AM, with 59% of daily flights taking off at noon.

330 flights are operational weekly from San Diego to Illinois as of October 2026. The most popular departure day for this route is Mon, with 18% of flights per week taking off on this day.