Cheap flights from Illinois to San Diego from $123

If you are unable to visit San Diego during the month of February, then departing from Illinois during the month January is also very affordable. Most momondo users find prices during this month for around $264.

The cheapest day to depart from Illinois to San Diego is on a Thursday. Travelers who choose to depart for San Diego on a Thursday will often find tickets for as low as $334. If your travel schedule is flexible, try to avoid departing on a Monday because tickets tend to average around $365. These prices are subject to change though, so be sure to set up a Price Alert for flights to San Diego.

The cheapest time of day to fly to San Diego is in the evening when flights can be purchased for as low as $306. Flights at noon are often more expensive with an average ticket price of $358.

Fly from Chicago O'Hare Intl to San Diego for the best Illinois - San Diego flight prices

You are more likely to see cheaper flights to San Diego from Illinois when booking weeks ahead of your departure date. In general, you can expect to find flights to San Diego for around $316 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to San Diego from Illinois for as low as $267 on momondo.

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

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

American Airlines, United Airlines and Alaska Airlines are the top three most popular airlines that fly to San Diego from Illinois according to our data. American Airlines is the first choice among our users, with 43% of people opting to fly with this airline when traveling to San Diego. Keep in mind that there are 8 different airlines that fly to San Diego on a routine basis, so you have a few additional options to choose from.

43 flights are operational daily from Illinois to San Diego as of September 2026. The most popular departure time for this route is 7:00PM, with 42% of flights per day taking off in the evening.

As of September 2026, there are 303 flights per week flying from Illinois to San Diego. The most common day of the week flights depart is Fri, with 17% of flights taking off on this day.