Cheap flights from Illinois to San Antonio from $118

If you aren’t able to travel during the month of October, then book flights to San Antonio from Illinois during September instead. Flights to San Antonio in September, while not as cheap as those in October, still average around $361.

The cheapest day to depart on your flight to San Antonio is on a Thursday when prices can be found for as low as $386. This is often the case because there is less demand to fly during this day of the week. Be sure to avoid booking your departure on a Sunday as prices are generally higher than usual. According to our data, the average ticket price to San Antonio on Sunday is $518.

According to our data, the cheapest time of day to fly to San Antonio is in the afternoon. momondo users have found flights departing from Illinois to San Antonio in the afternoon for as low as $397. 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 San Antonio are more costly in the evening, with an average ticket price of $414. Departure times in the evening fall within the peak daily travel times, which is why tickets can be more expensive.

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

You are more likely to see cheaper flights to San Antonio from Illinois when booking weeks ahead of your departure date. In general, you can expect to find flights to San Antonio for around $404 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to San Antonio from Illinois for as low as $330 on momondo.

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

Frontier, Southwest, and Delta are the most popular carriers operating from Illinois to San Antonio

United Airlines, American Airlines and Frontier are the top three most popular airlines that fly to San Antonio from Illinois according to our data. United Airlines is the first choice among our users, with 42% of people opting to fly with this airline when traveling to San Antonio. Keep in mind that there are 6 different airlines that fly to San Antonio on a routine basis, so you have a few additional options to choose from.

16 flights are operational daily from Illinois to San Antonio as of September 2026. The most popular departure time for this route is 9:00PM, with 41% of flights per day taking off in the evening.

As of September 2026, there are 115 flights per week flying from Illinois to San Antonio. The most common day of the week flights depart is Tue, with 25% of flights taking off on this day.