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$94+ Cheap flights from Illinois to San Diego (SAN)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 9/16. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — SAN
Aug 16 — Aug 231
Sun 8/16
Sun 8/23
1 adult, Economy
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Cheap flight deals from Illinois to San Diego

Cheapest flights from Illinois to San Diego
Explore the most affordable flight options available from Illinois to San Diego. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 17, 2026.

This Super.com deal was found by Cheapflights users on 7/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/108:08 pm
STL
-
SAN
1 stop5h 43m
Frontier
Mon 8/178:51 pm
SAN
-
STL
1 stop18h 59m
Frontier
Deal found 7/14$246
This Kiwi.com deal was found by Cheapflights users on 7/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/2512:46 pm
STL
-
SAN
1 stop10h 02m
Frontier
Mon 9/2810:36 am
SAN
-
STL
1 stop6h 39m
Frontier
Deal found 7/13$248
This CheapOair deal was found by Cheapflights users on 7/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/67:10 pm
STL
-
SAN
1 stop26h 56m
Frontier
Sun 8/98:51 pm
SAN
-
STL
1 stop19h 24m
Frontier
Deal found 7/12$250
This Kiwi.com deal was found by Cheapflights users on 7/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/910:35 am
STL
-
SAN
2 stops39h 24m
Frontier
Tue 10/136:25 am
SAN
-
STL
1 stop10h 50m
Frontier
Deal found 7/14$252
This Kiwi.com deal was found by Cheapflights users on 7/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/48:08 pm
STL
-
SAN
1 stop5h 43m
Frontier
Tue 8/113:03 pm
SAN
-
STL
2 stops26h 20m
Frontier
Deal found 7/13$254
This Kiwi.com deal was found by Cheapflights users on 7/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/138:08 pm
STL
-
SAN
1 stop29h 43m
Frontier
Thu 8/206:25 am
SAN
-
STL
1 stop10h 48m
Frontier
Deal found 7/16$258
This Kiwi.com deal was found by Cheapflights users on 7/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/56:41 pm
STL
-
SAN
2 stops16h 21m
Frontier
Tue 10/136:25 am
SAN
-
STL
1 stop10h 50m
Frontier
Deal found 7/15$259
This Kiwi.com deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/67:10 pm
STL
-
SAN
1 stop26h 56m
Frontier
Wed 8/123:03 pm
SAN
-
STL
2 stops26h 20m
Frontier
Deal found 7/17$260
This Kiwi.com deal was found by Cheapflights users on 7/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/298:08 pm
STL
-
SAN
1 stop14h 57m
Frontier
Wed 8/53:03 pm
SAN
-
STL
2 stops26h 20m
Frontier
Deal found 7/15$261
This Travelocity deal was found by Cheapflights users on 7/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Travelocity is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/58:10 pm
STL
-
SAN
1 stop5h 49m
Multiple Airlines
Mon 11/96:15 am
SAN
-
STL
1 stop15h 41m
Multiple Airlines
Deal found 7/16$262
This Kiwi.com deal was found by Cheapflights users on 7/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/118:10 pm
STL
-
SAN
1 stop21h 31m
Frontier
Mon 9/147:24 pm
SAN
-
STL
2 stops12h 16m
Frontier
Deal found 7/16$263
This CheapOair deal was found by Cheapflights users on 7/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/1612:46 pm
STL
-
SAN
1 stop25h 39m
Frontier
Sat 9/198:32 pm
SAN
-
STL
1 stop20h 43m
Frontier
Deal found 7/15$264

Find flight deals from Illinois to San Diego

Keep the following information in mind while searching for Illinois to San Diego flight deals. Data was last updated July 17, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$246
(Super.com)

One-way from

$94
(Alaska Airlines)

Popular in

June

Cheapest in

October

Average price

$357

Good round-trip deal

$335 or less

Good one-way deal

$167 or less
Provider with most accurate pricing for Chicago (CHI)-San Diego flight deals.
Search Deals
Provider most trusted by Cheapflights users for Chicago (CHI)-San Diego flights.
Search Deals
From Illinois to San Diego
Search Deals
One-way flight from Illinois to San Diego
Search Deals
Highest demand for flights based on searches. 13% potential increase in price ($46 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($7 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in July 2026
Search Deals
Price to beat on a round-trip flight from Illinois to San Diego.
Search Deals
Price to beat on a one-way flight from Illinois to San Diego.
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Illinois to San Diego that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated July 17, 2026.
Use the filters below to find and compare flights from Illinois to San Diego that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

ChicagoSan Diego

ORD - SAN

ORDSAN

Chicago O'Hare Intl

Wed 8/19

6:01 am-8:32 am

Nonstop4h 31m

San Diego

Sun 8/23

5:45 pm-11:59 pm

Nonstop4h 14m

$287

ChicagoSan Diego

MDW - SAN

MDWSAN

Chicago Midway

Mon 8/31

6:15 am-8:20 am

Nonstop4h 05m

San Diego

Tue 9/1

12:20 pm-9:05 pm

1 stop6h 45m

$294

ChicagoSan Diego

MDW - SAN

MDWSAN

Chicago Midway

Fri 8/21

6:15 am-8:20 am

Nonstop4h 05m

San Diego

Mon 8/24

10:40 pm-7:35 am

1 stop6h 55m

$297

ChicagoSan Diego

ORD - SAN

ORDSAN

Chicago O'Hare Intl

Thu 8/6

9:54 am-5:04 pm

1 stop9h 10m

San Diego

Thu 8/6

10:17 pm-7:56 am

1 stop7h 39m

$298

ChicagoSan Diego

ORD - SAN

ORDSAN

Chicago O'Hare Intl

Mon 8/10

5:57 pm-11:35 pm

1 stop7h 38m

San Diego

Sat 8/15

2:00 pm-11:57 pm

1 stop7h 57m

$298

ChicagoSan Diego

ORD - SAN

ORDSAN

Chicago O'Hare Intl

Thu 8/13

3:48 pm-7:55 pm

1 stop6h 07m

San Diego

Tue 8/18

10:40 pm-4:43 am

Nonstop4h 03m

$301

ChicagoSan Diego

MDW - SAN

MDWSAN

Chicago Midway

Fri 9/18

1:00 pm-9:00 pm

1 stop10h 00m

San Diego

Tue 9/22

10:25 pm-9:50 am

1 stop9h 25m

$307

ChicagoSan Diego

MDW - SAN

MDWSAN

Chicago Midway

Thu 9/24

2:00 pm-8:37 pm

1 stop8h 37m

San Diego

Sun 9/27

10:25 pm-9:50 am

1 stop9h 25m

$307

ChicagoSan Diego

MDW - SAN

MDWSAN

Chicago Midway

Thu 10/15

5:21 pm-11:39 pm

1 stop8h 18m

San Diego

Sun 10/18

10:00 pm-9:18 am

1 stop9h 18m

$307

ChicagoSan Diego

ORD - SAN

ORDSAN

Chicago O'Hare Intl

Mon 8/10

8:05 pm-10:34 pm

Nonstop4h 29m

San Diego

Sun 8/16

6:18 am-12:37 pm

Nonstop4h 19m

$308

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/16

Showing 1-10 of 60 resultsSorted by cheapest first
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Best time to book a flight from Illinois to San Diego

Have a flexible travel schedule? Discover the best time to fly to San Diego from Illinois with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Illinois to San Diego

What is the cheapest month to book a flight from Illinois to San Diego?

Currently, February is the cheapest month in which you can book a flight from Illinois to San Diego (average of $225). Flying from Illinois to San Diego in March is currently the most expensive (average of $399). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from IL to SAN?

Find hourly flight availability from Illinois to San Diego. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated July 17, 2026.

A simple way to save on the total cost of your ticket is to fly from Illinois to San Diego in the evening. If you’re flexible enough to do this you can expect to save up to 24% on your trip compared to booking a flight at noon.

Weekly flight availability from Illinois to San Diego

Explore weekly flight availability from Illinois to San Diego. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated July 17, 2026.

The most flights from USIL to SAN are scheduled on a Friday (49 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (27 on average).

How much does it cost to fly round-trip from Illinois to San Diego?

How far ahead should I book a flight from Illinois to San Diego?

To ensure you get the cheapest price possible for a flight from Illinois to San Diego, you should look to book at least 47 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.

What is the cheapest day to fly from Illinois to San Diego?

Use this chart to determine the cheapest time to fly round-trip from Illinois to San Diego. Price data was last updated on July 11, 2026.

Travelers seeking maximum savings on their Illinois to San Diego flight should consider departing on Saturday afternoons when fares are most often at their lowest. Saturday at noon flights should be avoided if possible as fares are typically the most expensive at this time.

Related info for your journey

Find useful and relevant information for your journey from Illinois to San Diego. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airport do you fly into for flights to San Diego from Illinois?

    Most people fly into San Diego (SAN) if they book a flight to San Diego from Illinois. San Diego is conveniently located just 2.6 mi from San Diego’s city center.

  • How long is the flight from Illinois to San Diego?

    For as low as $294, Alaska Airlines can have you in San Diego from Illinois in 4h 05m. Illinois and San Diego are separated by a distance of 1725 mi. Both multi-stop and nonstop flights can be found to your destination and back.

  • What are the cheapest airlines to fly from Illinois to San Diego one-way?

    To fly one-way, consider booking your trip with Frontier, which is currently one of the cheapest options available, starting at $63. Hawaiian Airlines flights start at $69 while deals on Southwest start at $76 one-way.

  • What are the most popular routes from Illinois to San Diego?

    Most travelers choose Chicago O'Hare Intl - San Diego, Chicago Midway - San Diego or Lambert-St Louis - San Diego when deciding on the best route from Illinois to San Diego.

  • What are the most reliable airlines from Illinois to San Diego?

    Consider Air Canada (80%), United Airlines (76%) or Japan Airlines (75%) when booking your flight. These represent the most reliable airlines when flying from Illinois to San Diego.

  • What are the cheapest flights from Illinois to San Diego?

    The cheapest flight price from Illinois to San Diego is $138. On average you can expect to pay $731. The most popular route, (Chicago O'Hare Intl - San Diego), can usually be booked for $253.

  • Can I find deals for flights from Illinois to San Diego that include hotel bookings?

    Yes. In addition to deals on Illinois to San Diego flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Illinois to San Diego?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Illinois to San Diego.

  • Can I find deals for business class flights from Illinois to San Diego?

    Yes. Cheapflights offers flight deals from Illinois to San Diego by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Illinois to San Diego?

    Currently, February is the cheapest month in which you can book a flight from Illinois to San Diego (average of $225). Flying from Illinois to San Diego in March is currently the most expensive (average of $399). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Traveling to a place near San Diego?

Book flights to San Diego if you plan to visit one of these locations
El Cajon
National City
Chula Vista
Poway
La Mesa
Coronado
Santee
San Ysidro
Julian
Lemon Grove

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for Illinois to San Diego

See prices for flight routes from nearby airports that may be better suited for you.
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Top 7 airlines flying from Illinois to San Diego

Discover the top 7 airlines that operate flights from Illinois to San Diego. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated July 17, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$83Average$241FlexibilityNo cancel feeOn-time62%
Hawaiian AirlinesCheapest$138Average$237FlexibilityNo cancel feeOn-time85%
Alaska AirlinesCheapest$152Average$304FlexibilityNo cancel feeOn-time75%
American AirlinesCheapest$156Average$448FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$157Average$391FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$177Average$343FlexibilityNo cancel feeOn-time63%
DeltaCheapest$186Average$328FlexibilityNo cancel feeOn-timeN/A

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